Agreed, which is one of the reasons I always try to get an aisle seat. If that's not possible I generally go without, or at the very least wait until I have multiple reasons to get up (toilet break, etc) so as to cause minimum possible disturbance. But then part of me thinks its rude even to ask for a refill - I've had my share, who am I to ask for more than others? Again my experience in Y on other airlines is that there's only just enough on board to go around, asking for more likely means someone else is deprived.