ChrisG's cranky ornery attitude towards losing (aside from today), general humorlessness, and attitude towards Evo, including "ur a faget"-gate. I don't know if it falls under the wrestling fan the definition of heel, but he seems to have a highly impacted cloaca or something. I realize that's what helps him win, but it also makes him hard to like.
Infiltration is not heel, he's just evil looking and cold/calculating. There isn't anything objective to make him seem like he has a poor attitude or whatever. He plays, wins, or loses, he's a machine. You don't see much of a reaction either way from him.
But when you're up top, you get gunned for, that's how it has to be. Nobody gets to be the 100% loved and well-respected champion because other people will always wanna be the champ.