Somewhere I heard that if you pick up a kitten and hold it under it's front legs leaving the back legs kind of dangle (sounds bad but it isn't) you can tell there personality by how much or how hard they struggle with their back legs.
I'm not sure I believe it unless you can actually train it out of them. My son and daughter in law have on cat that did a lot of fighting. My son was merciless in holding her like that when she was small. She id calm down. She's a really nice mannered cat now and is really tolerant with the kids.