Not only the opposite of appreciating an act or gesture, but actually hating the act or gesture and its origin, usually an unapprecihative person. A good countermeasure to a sarcastic or rude comment.
Tony: Damn dude, you got ganked!
Me: Thanks asshole, I apprecihate it...
What you get for putting your own life on hold to help a friend in need.
I don't mind putting my shit on hold to help you out, but instead of gratitude... You avoid me when I need help. That shows how much you appreciHATE me.