Quote Originally Posted by Segev View Post
They have value as means of establishing whether you can trust somebody to share a particular set of morals or ethics. Yes, you CAN trust that a Lawful Good person isn't going to backstab you, but will deal reasonably with you and tell you if there's a conflict of interest they perceive. Yes, you CAN legitimately worry that the Neutral Evil person might kill you in your sleep; it's certainly within his moral and ethical capacity. And as "team jerseys" that are not so much donned and doffed by applying the label, but rather are endemic parts of the creature's being based on the person they are, they work just fine.

You can have your exceptions, if you want them, but they are just that: exceptions. And they're "the evil guy who works with good guys," not, "the good guy who proves that good doesn't actually mean good."
See, thing is, I've occasionally taken a character concept or personality from fiction (or history in a couple cases) that just seems to contravene all D&D style alignment.

I've had the selfish evil dude who was totally honorable and trustworthy, legit improving the world and saving people. Everyone thought he was LG except that he wallowed in glory & fame, plus his enjoyment of slaughtering team monster was a bit creepy. It caused a huge argument when he took an action that was unquestionably evil. Everyone agreed it was in character, but they all thought "LG" meant different things and started arguing about it. I ran a LG character once who committed terrible acts of evil simply by being a clueless twit who believed he could do no wrong. The character was a great person but never thought ahead, never questioned stuff, and always assumed they were in the right. Ticked all the classic LG checkboxes, believed and tried to do good all the time, never felt guilt because he believed liars and thought his absolute intention to do good absolved all mistakes. That game had more mature players, it wasn't a argument but several people couldn't agree on the character's alignment.

My personal experience has been that D&D style alignment is too broad, too vague, and too loaded with cultural baggage to be workable for anything but the most stereotyped characters. Even your "evil -> kill you in your sleep" and "good -> no backstabbing" is a reflection of a cultural assumption.