They gossip in class and sneak sweets from the kitchen. They help each other out of jams and get each other into jams. They detest bullies and love their folks. They aren't fond of spiders. Rowling's theme, as in her first three Potter books, remains Harry's growth and survival.
Wizards seem to love competition.
She defies stereotypes. Boys whine, girls are smartest, ugly wizards are nice. But in the world of Rowling and other good children's authors through the decades, good is rewarded and bad isn't. And in the world of Rowling, children are brave and powerful. They are the heroes.