There are no unanswered prayers

Why is it, do you suppose, that in evangelical Christian sub/culture, we seem to believe that the only answered prayer is one where we get what we want?  As if the completely reasonable answers of "No" or "Wait" (which really sound the same practically speaking) are not actually legitimate answers for God the Father to give His children when we ask for something we, in all our finitude, want.

It's in songs, in church sermons, even in the words of some of my favorite contemporary bloggers.  It makes me so very sad.  Do we really believe that God just ignores some of our requests for some reason?  That He's not listening?  Where did this traditional view of things come from? 

Any insight you have would be appreciated.