1) If God is perfect and infallible, praying is useless because you are then asking God to change His plans, meaning that He isn't infallible.
2) If God is all-knowing, then we cannot have freewill because freewill implies a future with no predestination.
3) If God is all-loving and benevolent, then He cannot be all-powerful, because if He were, He would design a world with no evil.
Superb Opinion