Unintended consequences of rule changes

[Jay R]

We talk about houserules and rulings in general terms. I though we could use a thread about actual examples of rule changes that have been used, and what unintended consequences occurred. Please focus on actual rule changes you've seen, and actual effects you witnessed, not guesses or hypotheticals.

Here's one example:

In a 2e game some years ago, the DM gave us (and the monsters) full hit points. The 3rd level paladin didn't have 3d8; she had 24 (plus CON bonus). To be fair, he also gave full damage to magical effects like magic missiles, fireballs and lightning bolts.

As near as I could tell, I was the only one who ever figured out that by nearly doubling both the hit points and magical damage, the DM had effectively cut the value of weapons in half. Of course, this also made magical attacks relatively more valuable than buffing the fighters.

[Tinkerer]

So many unintended consequences. Definitely one of the most common one that I've seen is allowing a trait which the party has to cover one that they don't and making it unintentionally more effective. For instance one party didn't have the tracking skill so the GM allowed perception to cover it. Unfortunately due to perception being an easy skill in the system and tracking being a hard skill the GM never realized that they had just made the tracking skill not only completely redundant but in fact a definite step down.

[1337 b4k4]

The go to example of this for me is an official rule change. The change from xp for gp in early D&D to the primary xp source being monsters “defeated “ (read killed) fundamentally altered the game from one of dungeon crawling thievery and adventure to one of planned combats and murderhoboing

[Vitruviansquid]

Playing Savage Worlds in a friend's game who is new to GMing. I had a character using a sawn-off shotgun, which is already insanely lethal according to the game's rules. I rolled poorly in one fight and got stunned often to be unable to attack, as well as rolling poorly when I did attack, and the Gm tells me to double the number of dice I roll on hits as a speedy buff.

In Savage Worlds, damage dice give bonus rolls when you get the largest number, so simply having more dice can cause my damage to skyrocket unexpectedly. I quietly did not roll the extra dice he told me to and continued to play as normal... and indeed my character was still insanely lethal.

[2D8HP]

Your example relating to hit points sparked a memory:
One "variant" (that's what we called "house-ruled" long ago) of TSR D&D that my table used decades ago (I think I got the idea from Different Worlds magazine) was to make CON = total HP no matter the level, which made low level PC's less "squishy" and high level PC's more down to earth.

It worked great!... at first.

Notable results:

Classes other than Fighter were actually played.

Without being able to gain extra HP upon gaining a level, we stopped playing the same PC's.

Almost every session had a new batch of PC's.

[Spore]

In Degenesis (a rather small German system and more of a showcase than a good system) you get 'ego points' back for acting within your character concept. The game works similar to WoD (d6 dice pools instead of d10), ego would be willpower.

A few problems though:
1) Nonlethal damage damages ego. So a scrawny boy can duel a huge muscular biker and win because the biker has almost no willpower or faith (directly linked to the ego pool).
2) You recover 1 point for every night's rest.
3) You can burn ego to heavily improve your combat performance. So if you maintain a 5 minute adventuring day every week or so, you can do insanely godly things.

What did we do? We changed nonlethal damage to be like in Pathfinder, HP damage. Instantly nonlethal options became a non-option. Then, some concepts offer their ego return more often than not (like the conservative gets it every time he defends the status quo which is quite often in heroic journeys; the destroyer only if he won something or killed someone). Third, ego now tends to be pooled (since the DM cannot drain the pool other than through combat) and if it fits the character tends to be even used for active murderhoboing. It is not: "My ego is full, my character is healthy and happy." It's more like a "I would waste my ego regen tonight. Let's kill someone for their possessions."

[Guizonde]

i'd never heard of exploding d20's in pf before. my dm has it as a house-rule.

... i routinely rolled 40+ on acrobatics checks at level 3. i had a character concept of using a grappling hook for doing those stunts. instead, everybody assumes my inquisitor has a "fly/flea-hop" sla usable at will.

my current record (with team boosts and exploding dice) is rolling a 67 on an intimidation check. my highest acrobatics roll? 64. did i mention i'm only level 4? we punch stupendously above our weight as a routine. our team's penchant for looney tunes antics and comic short-sightedness stops us from curb-stomping the campaign in an overpowered rampage.

67/10 would recommend for silliness.

[PrismCat21]

3.5 DnD
My first DM had quite a few houserules. The main reason was because his girlfriend wanted to do everything that everyone else could, and do it better. If anyone could ever do anything better than her, they were cheating somehow.
Some of my least favorites were...

Bonus spells for a high ability score could be used as early as level 1, and you got bonus spells based on the score itself, not the modifier. - People were insanely overpowered at low levels. This means that dipping became common, but discouraged to anyone but the girlfriend.

No one could actually die. If anything resulted in your hit points dropping to -10, you were just knocked out and 'got better' later that day. - The DM couldn't understand why we started becoming reckless and unafraid of danger. He thought we were being unrealistic.

There was no penalty when shooting into melee for anyone, If dual-wielding, you only took half of the penalties if any at all, when reduced to negative hit points you automatically become stable. - Basically, everyone got Precise Shot, Two-Weapon Fighting, and Die Hard for free. Of course, the DM didn't bother to tell me any of this until a couple of sessions after I choose to play a Ranger, making my combat style and feat choices pretty much irrelevant.

(The best one)Attacks of Opportunity did not exist, AND we could make full attacks while moving AND could attack with an off-hand weapon with every attack with a main-hand weapon. No mater what we or our enemies did, shooting into melee, casting spells adjacent to an enemy, running circles around enemies, we could do everything freely. - When I multiclassed to Scout(Swift Hunter), the party saw the obvious exploit and nearly everyone became a Scout(Dual-wielding). They would run in tight circles around an opponent, activating Skirmish, and attacking 4-6 times before moving away. The opponents could do nothing to stop them except attacking on their own individual turn.
Completely ridiculous.

[Jay R]

In Flashing Blades, you name the body part you want to hit, and roll twice on the hit location table. The one closest to where you wanted to aim is the real location.

So in one game, I suggested the following rule:

If a fighter rolls his expertise or less on 3d6+6, he hits his target. Otherwise, go to the table.

My rationale was that poor fighters should have next to no aim. Average fighters should have occasional aim. Masters should aim well. Masters Superior should hit whatever the hell they want to.

That makes sense, but since almost any hit to the head kills, a somewhat better fighter had an incredibly better chance of killing on a single shot.

[tensai_oni]

Here's a DnD 3e/3.5 classic:

What gets changed: WBL tossed out of the window, forget simply shopping for magical items, they are extremely rare and precious artifacts.

Intended change: Reduce the Monty Hall feel of the game where everyone is overloaded with magic. Run a low magic, down to earth setting.

Actual change: Reliance on magical items is still there (for martial classes), it simply isn't satisfied. Martials are even more underpowered than usual. Nobody plays them, say hello to a party full of spellcasters who aren't meaningfully inconvenienced in any way.

3.5 DnD
My first DM had quite a few houserules. The main reason was because his girlfriend wanted to do everything that everyone else could, and do it better. If anyone could ever do anything better than her, they were cheating somehow.
Some of my least favorites were...

Two of these (no one dies, no penalty for shooting into melee) are good changes. Shame about the rest though.

[Frozen_Feet]

Lamentations of the Flame Princess didn't actually have rules for learning languages, only for knowing them.

Hacking in rules for learning them lead to multiple characters spending significant game and downtime to teach languages to each other. Which sort of made sense since by that point they were merchants turned privateers turned pirates sailing all across the world.

[Quertus]

I really should have hundreds of stories to contribute, yet, sadly, this is all I have offhand:

I had 2 GMs try to make 2e (or older) D&D Wizards more playable by letting them cast spells from their spell books. For one, the extended casting time of using the spell book just made wizards more vulnerable to people attacking their spell books. However, it was under the second one that things got interesting.

This GM decided that, to balance the potential power granted by casting straight from the book, that spells used this way would function just like scrolls, and be erased. Enter high strength wizards who can lug around more books with more copies of their spells. And Wizards getting others to carry their books for them. Downtime became a big thing. But, in trying to give the Wizard more stamina, they'd actually given the party less. Because, now, they were burdened down with spare spell books, and would need to go back to town sooner to unload the weight of treasure, monster corpses, etc.

Then enter me. I note that the Copy spell will copy itself many times over. And those copies can be used to create even more copies of Copy. And I also note that "use like a scroll", well, one can attempt to use scrolls of spells beyond your normal caster level. Once I started spamming captured high-level spells, the GM realized that maybe this wasn't working quite the way that they'd intended.

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One GM decided to make healing spells automatically maximized for free outside of combat. Sounds good, right? Unless you're specifically built for it, combat healing is usually a pretty bad plan. So now good tactics and good role-playing are aligned with fun play, and the Cleric can take much more interesting actions in combat without the party complaining. All good stuff, right?

Problem was, the GM gave an XP bonus for certain actions - one of which was casting healing spells in combat. So, the reward was for taking actions which were bad tactics, bad for the party, and which could not be justified in character. Why are you casting a healing spell on me now, rather than doing something useful now, and healing me after combat, when you can pay attention to what you're doing, and heal me better?

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Early on, I had a GM who wanted to play high-level games - higher level than most of my characters. So I had to create new high-level characters from scratch. This would have been fine - there were rules for leveling, and I could even fake out a semi-random spell book - except that I loved making custom items for my characters. Never anything ridiculously powerful, mind - a combination Heward's Handy Habersack & infinite supply of trail rations, or an ever-bleeding sword, for example.

For whatever reason, this GM didn't like my ongoing rule of cool item selection. So they told me to make a new character. They said I could have any items I wanted, so long as they were from the book.

And thus was born my love of optimization.

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And, of course, there's one everyone knows: that balancing by spell slots produces the 15-minute adventuring day.

[GAAD]

So my house rule involves multiple nat 20s in a row. This counts for everyone: Roll a 20, you roll again. If you fail, you succeed. If you succeed, you crit. If you 20, roll AGAIN. If you fail, you crit. If you succeed, you triple whatever the max crit was. And if you somehow manage to roll 3 twenties in a row... congrats you lucky bastard. You WIN. As long as it’s possible for you to do it, you do it perfectly. Fighting a monster? It’s dead. Negotiations? You got everything you wanted. Climbing a cliff? You manage to make a trail and nobody else has to roll.

My players have only managed to roll 3 consecutive twenties once.

They were trying to blackmail a god.

In the words of the sorcerer: “Some parties complain about railroading. This party robbed the train.”

[vasilidor]

critical fumbles: no one ever makes it to second level, at least without gm caveat any how. always horribly maims or kills themselves.