Does Jay Cutler Have a Legitimate Reason To be Pissed off in Denver?

I understand that he had a probowl year, and was not the reason the Broncos had a miserably inconsistnt season, i mean, having a defense might have helped. But, just because his name was mentioned in a trade, does he really have a reason to be as upset as he seems to be? Isnt it every teams duty to look into upgrading, in their oppinion, any position if they can?