I have yet to get a real answer to the question of why anyone would pray to a god who planned out everything long before we were born anyway. God is not going to change his enormously holy mind just because some pipsqueak asks him to, or he would be jerking reality around willy-nilly every few seconds.
Two different people ask for the opposite stuff to happen and what, god makes it rain on the farmer's crops and
not rain on the wedding at the b and b next door, the same weekend? Or does reality branch off into multiple lines where it rains on the wedding but the crops are saved in one, and the wedding is a sunny success, but the crops die in the another?
Anything god wants to happen is already happening. How could it be any different? We are already going to believe, or not. We are already going to be saved, or not. So much for free will. The Hindus have it right. It is all karma based--except, for some strange reason, they pray, too.