Hussar
Legend
But there are just some people who want to play a game (or an evil character in my case) that is just incompatible with the type of game the DM wants to run. I don't view my players as disposable or replaceable, but I have limited time to game and at a certain point I simply can't cater to everyone. I explain to people that are interested in my game my general style and I'm very up front about what kind of campaigns I run. That I'm open to feedback and suggestions but that I prefer the PCs to be the heroes of the story, not "edgy/dark anti-heroes". In addition just because someone isn't interested in my campaign, doesn't mean they aren't welcome to come over for board game night or that I think any less of them.
When we discuss the campaign we're going to run we bounce around ideas, but ultimately as a DM I have to be inspired and have a vision so that I can paint the world as a living vibrant place. A player can have a PC that's little more than stats on a page and still be fun to play with. But if the campaign doesn't motivate the DM I don't think it's not worth playing.
Well, there is some truth to that. If you run into a situation where there just is no possible compromise, then fair enough.
I was presuming here though that, since the player had been playing good characters, the player didn't hate playing good characters, but, rather that the player just wanted to try an evil character.
The whole point is, no one, not the DM nor the players, should feel compelled to play something they don't enjoy. The player, in this case, should simply default to the second choice - play a good character - and no harm, no foul. Obviously trying to compel you to run the game is wrong.
But, it is equally wrong for the DM to try to compel the players into playing something they don't want to play. In your case, the player had been playing good characters before, right? So, the player wasn't opposed to playing a good character - the player didn't hate playing good characters. At least, that's the assumption I'm working off of. Therefore, the player pitches his idea, learns that someone at the table hates that idea, and moves on. The same way that a DM should do the same thing. Pitch an idea, if someone at the table hates the idea, move on.
Again, I'm presuming everyone at the table is working in good faith to make the game the most fun it can be for everyone at the table. No one, ever, should be forced to play something they really don't like. And, holding play hostage (you either play what I want to play, or there's the door) is a terrible model for how to DM or play.