God answers all prayers of His children. Sometimes He answers yes in a very obvious way and sometimes He says no. The hardest part for us, is that we don't always recognize the answer because He doesn't do things our way. Quite often we look back and realize if He had answered our prayers the way we wanted, we would have missed another blessing.
It's hard to explain to people who look at blessings as something to enjoy physically...
Well.. Sometimes good things happen when you don't ask god too. And sometimes bad things happen when you ask god for them not to.
Basically, it's all random. You feel vindicated when it goes your way, but you rationalize it away when it doesn't.