I imagine the snap to reality would be hard to deal with, especially since as a toon, Henry doesn't really belong to it either. Not anymore. It was one thing to be goofy and casually indulge the odd instincts around other toons, but his family knows what he's usually like. The creeping dread of losing your identity is probably easier to ignore than the fact that sometimes he's just going to act like a clown without realizing it's happening. Man's got his pride.
It’s hard to even wrap your head around all the things that would be different, in small but major ways. He’s gone from a fairly reserved and somewhat serious guy to someone who has to actively work to hide what he’s feeling at any given moment. The way he expresses his emotions is different, the physicality of how he moves around has completely changed.
It’s humiliating in the standard way of making a fool of himself on a regular basis, but also in a whole different way; usually a guy his age is done, or close to done, figuring out Who He Is. Now suddenly he’s fumbling with that concept all over again, and very visibly. He may not be completely lost or rewritten, but that makes it all the harder to parse the difference.