When my daughters get together they are extremely silly and have so much fun together. The other day we were also with another friend's daughter who is a bit younger, less verbal, just not as strong of a personality. The girls were giggling hysterically and calling her a poopy head, saying they wouldn't share their food with her, etc...all while laughing hysterically. My friend and I are very sensitive about not wanting "mean girl" daughters so help us understand the difference between being silly and not truly trying to be mean and consciously being unkind which I really don't think they were doing.