Ari Graynor — who stars in the CBS pilot “Bad Teacher,” based on the Cameron Diaz movie — had a bad teacher of her own. “She was teaching us about mass, matter and volume in sixth grade . . . at the peak of your awkward phase,” the actress told us. “She was bringing up students, and asking, ‘Who has more mass?’ She brought me up with this teeny, tiny little girl. It has haunted me all my life.” The new show also stars Sara Gilbert and former “Sex and the City” star Kristin Davis.