Have you ever been in a situation where you have been completely devalued by another coworker?

I don't know if he even realizes that he is doing it or maybe he does but I'm not sure why. I can only think that it is because... a) he doesn't like me as a person, b) he is threatened by me (I wouldn't consider myself an intellectual slouch), or c) I have higher work standards and voluntarily take on additional tasks while seeking to improve internal processes. It could be a combination of all of these or something entirely different. I'm really not a conceded person, I am just trying to figure out why he is constantly talking to and treating me like an infant. No idea is a good idea unless it comes from him and he is completely condescending.