My older daughter is 10 (11 in Aug) & has lots of attitude. No matter what we do, she still has it. Punishment doesn't seem to matter. Since school has been out, she's been a lot better. I think a lot of it had to do with the little girls she was hanging around.
Attitude, mood swings, a lot of emotion. Also they are like rubber bands at this age, pull away and then snap back, they want to distance themselves emotionally but are not ready to so be prepared to be loved and hated on a regular basis. There is a lot of fun stuff too though!