I personally hated hearing this growing up. "Be nice" is one of the most harmful things you can tell a girl to be. It makes us question our judgement and think we are wrong for feeling our feelings. I also read an article in Elle where Brie Larson said she ad-libbed the line about "be nice" It was Larson who came up with the line in ROOM, screaming at her mother (played by Joan Allen): "I'm sorry I'm not nice anymore!" In the movie she says something like (Im paraphrasing from memory), "if I hadn't heard your voice in the back of my head to "be nice" maybe I wouldn't have stopped for him and I wouldn't have been kidnapped and locked up for 7 years!" That line stuck out to me because I totally heard "be nice" and hearing that command made me so angry as a girl. Now I'm glad to know I'm not the only one that feels that way about the words "be nice."
Angry Little Girls
Read Angry Little Girls comics starring the Angry Little Asian Girl