Hilda's Cat Fight with Gina is this in one of the very first few episodes, especially leaving with a one-liner after winning and leaving with a lock of Gina's hair.
Hilda: Looks like we own you five-thousand dollars...(looks at the lock of hair and drops it) and fifty-cent.
Betty goes Beware the Nice Ones in "Filing For The Enemy", calling out Wilhelmina's behavior and standing up to Marc.
Wilhelmina: And I love that blouse.
Betty: No, you don't.
Marc: (Touches Betty's nose)
Betty: (Grabs Marc's finger) You will not poke my nose anymore.
In the pilot episode, Daniel goes along with the plan to upset Betty into quitting...until it ranges into outright humiliation by having her pose for the camera. When everyone laughs at her, and she reaches her breaking point, a furious Daniel puts an end to the whole thing. It's the beginning of a beautiful friendship.
Claire's friendship with Yoga, which was also heartwarming. Particularly awesome was their escape.
"This is happening!"
Amanda beating Sofia with her purse after she had humiliated Daniel live on television.