They've never talked crap about other pop girls.
Britney kinda did but that was in response to other shading her (Christina, Avril). She never started any drama
Adele and Bey. Adele has never uttered a foul word about any of her peers and Bey says nothing about anyone unless she has something nice to say. Britney is sweet too -- she's gotten snippy at moments (#YouWantAPieceOfMe ), but not towards anybody that didn't come for her first.