His reaction on Giselle.
I love that ep, one of my all time MEGA FAVSHaha I love that!
I also love when Wes and Cordy are explaining to him the Darla-Angel-Dru relationship and it kind of wigs him out. Can't remember exact dialogue but I do love that.
And in "That Old Gang of Mine" when Gunn faces his old friends, and tells them that he's not with Angel because they're friends now but because Angel has "the mission" right so to speak.