She was generally a funnier more lively character during seasons 4, 5 and 6 when she was human. I think in season seven, she was dealing with a lot. Getting her vengeance powers back; killing those frat boys which really got to her and the break up with Xander. She was still funny in season seven, just not really her normal self, I would say.
In S3 she was awesome cause she was mean and evil and the way Emma did it was cool.
charmingslayer agrees: Yeah me too espicially the whole "And i'm failing math" LOL