If I showed you scripts from my first few movies, the descriptions of my characters all said 'the ugly girl'.
Sometimes I'll watch a movie, and it's got some big star in it playing a working-class person, and the character is in a grocery store, and you can kind of tell, from just watching the scene, that this actor doesn't do their own shopping. So you have to have some sense of reality.
As a character, it's very interesting to play someone who wants to change their life and have him change it.
There are actors I know personally, or I've heard them say, "The less known about me, the better, because I just want people to think of me as the character." I think Matt Damon said that recently. He has a point and I think I get that.