Ok this is a bit serious, and perhaps strange coming from me.
A friend got dumped recently and talking to him was a strange experience. He kept listing down all the things that he had done for the girl. He kept harping about how how she could have dumped him.
Now I beg to differ here.
I think no one does anything for anyone in a relationship. You do the things you do because of how doing those things makes you feel. Nothing less, nothing more. In the throes of the honeymoon period of a relationship doing things for the other person, the smile it brings to her face makes you feel so good that you'd go out of your way to do those things.
But when bitterness sets in, that fact should not be forgotten. You still did those things for your own happiness and no one owes you anything for what you've done for her. And its just cheap thinking that someone can "owe" you love/friendship.
And anyway would you want a relationship based on "owing" and "obligations" and "gratefulness" ? I think not.
Sorry for the serious-ish tone. Will write a funny, mindless post soon to compensate for this...