I think his "Yes!" thing originally started as an annoying heel-ish catchphrase but the fans seemed to latch onto it. However, since he just turned heel, it might be a bit weird for him to suddenly become a face again, so I guess the only logical thing they could have done was have him think that people were copying him or trying to mock him.
Seems to have died down a little bit recently, people were thinking it might become the new "What?"
