The scene where Jace is like to Simon in CoB, "You just want to sleep with Isabelle" :P And the scene in CoG where Jace goes to Clary's room and tells her he loves her!
When Alec kisses Mangus in front of everyone if City of Glass.
یا the really bitter-sweet scene when Jace tells Clary that if he uses the word sister enough in regards to her, it'll lose it's meaning and he'll be able to stop loving her (or something like that. I don't remember exactly what he said).
