I feel like I have a theme for an adventure or an enemy or even just a spell and I ca

[psycopuppy]

A recent example is my players were fighting four golems that I had reworked to exemplify certain emotions (I think they were fear, doubt, insecurity, and...don't remember the last one.) Cool idea I thought, and when I created their abilities I thought they were perfect. But running through them with my players they came off as meh. Same with this "puzzle room." The basic idea was they confront the trauma that made them turn to a life of adventuring in the first place. Lots of roleplay, themes, everything my players love. It ended up going over like a lead balloon, with me finally spoon-feeding them hints to get them even begin to understand what they are supposed to do (after several hours) and by the end we were all just glad to be done with it. Don't get me wrong, once they caught on they really enjoyed it, I just think they were not in the mood to deal with that this session.

Any tips on expressing a certain theme for, say a monster the players just meet?

[Skrum]

Sorry, is there a question? Not every session goes over as well as we want. That's intrinsic to dm'ing

[SpikeFightwicky]

Do you mean, how to get your players to engage with the themes? The thread title looks like it cut off, so I'm not 100% the full question.

[tKUUNK]

1. Keep it simpler than you think it should be.
2. Remember you're DMing, not writing a novel. Nuances that work well in books are often difficult to convey at the gaming table.
3. Make your in-game "hints" SUPER obvious. Most people who play this game have great imagination, so if you leave them guessing about details, they will (sub)consciously invent their own. So fill in more of the blanks than you might think would be necessary.
4. Use foreshadowing. Before the players get to the location you described in the OP, maybe they heard from nearby farmers that the place draws out emotions. Set it up with lore drops ahead of time.

And mostly

5. We all have those "flop of a session"s from time to time. So dust yourself off and move on with the expectation that next session will be a complete blast!

[Mellack]

Adding in to the other suggestions:

Keep your solutions open ended.

One of the best parts of RPGs is that they allow creativity. There doesn't have to be "the" solution you have to lead them to. Often times players will come up with ideas you never planned for or even considered. And if they are not figuring out what you thought they should do and the game is getting bogged down, let one of their ideas be the new solution and get the game moving.

[kingcheesepants]

So what was the exact problem with the golems? Is it just that golems don't have very exciting stat blocks and there wasn't really anything strategically or terrain wise to play with and thus the combat kinda fell flat?

I think the basic idea of having metaphorical and symbolic encounters is fine but start by making fun encounters first. Make a fun puzzle or combat and then reflavor it to fit the theme you're going for. And remember that while RP of course happens during puzzles and combats, the kind of heavy introspection and soul searching type of RP probably doesn't fit with a combat or puzzle. So don't try to make your puzzle or whatever shoulder all that weight.

[Fiskco]

A trick I use for designing these types of encounters is try and think of at least three possible solutions to the puzzle/situation outside of the players creativity in the moment.

For instance, if you have a door that can only be opened by putting an orb in a slot, you run the risk of them missing that hint and being unable to open the door. A better idea would be to list out some potential ways they can open the door to prepare ahead of time:
They players find the orb and place it in the orb shaped hole in the door to open it
The players investigations of the door and find an arcane mechanism which can be triggered with thieves tools, or a round magic item they do not currently possess
A party member can attempt to force the door open, though it is difficult
after spending a long time and making a lot of noise attempting to open the door with no success, a monster patrol on the other side opens the door to investigate what's going on