This made me want to weep. I think that sometimes as adult children, we get angry if we feel our parents can't see us as anything other than their children, but we forget to try and see them as anything other than parents. That means that you do things for them without seeing it as a favor, like Polly said.
I wish I could send this to my brother and he would read it and think about it really hard and change the way he thinks about our mother. That won't happen because it won't. Everything he does for her is a favor (and he thinks he's being the good son) and everything she does for him is his due. Haven't quite figured that one out yet.