Matthew 6:7-8

But when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking. Be not ye therefore like unto them: for your Father knoweth what things ye have need of, before ye ask him.

I know it is hard to believe, but God does know what we need and he gives it to us when we need it. Sometimes it is not what or when we would like, but it is always the right thing.