Do I have to be Happy with God to Pray?

In I Samuel 1:10 we're told that, "In bitterness of soul Hannah wept much and prayed to the LORD." By the way, God answered that prayer. Hannah was praying for a child, God blessed her with the boy Samuel who would grow up to be one of the heroes of Jewish history. We absolutely don't have to be in a happy frame of mind to pray. In fact, God welcomes our honest prayers (including those where we're upset or don't understand God) far more than he ever will a fake attempt to get what you want from him through flattery. By the way, God knows your heart anyway, so you might as well be honest and admit to God that you're confused, sad, tired, and yes, angry.
Why was Hannah praying to God in the first place? Hannah went to the temple to pray precisely because she believed that God was in control of the world; that he was the one who could answer her prayer, and that it was a waste of time to ask anyone else for a miracle. Hannah HAD faith. Not a happy go lucky, all is right with the world kind of faith; but rather a real, down in the trenches, beaten but not broken, kind of faith. Real faith. And God answered her prayer, not in spite of her bitterness and weeping, but because of it.