So, what's the most "No but I wanna do it though" character you've ever played? Meaning a character you had to heckle with the GM to play, one that was generally not received well when you first introduced them, and required some pushing to get into the game?

Was it more about the rules, or about a concept that felt like it didn't fit? How did it go, and did the character end up surpassing expectations or going as badly as expected?