I'm with Craig and Lucky. It isn't the asking; it's the tone. I love doing favors. But if the person who's asking for a favor is already disrespecting me by being rude, it's a lot harder for me to grant their request.

It should be enough to simply do the thing that promotes harmony, whether or not the recipient is grateful. I wish I could get over the need to have people appreciate the good and helpful things I do. It usually isn't that hard, but on airplanes, when people are crammed together, the instinct to protect one's tiny patch of territory is very strong.