There are hundreds upon hundreds of different religions, and different gods these religions believe in. Thousands, if you count all the little sub-sects separately. Tens of thousands or more, if you count every religion throughout history that anyone's ever believed in. Even among today's Big Five, there are hundreds of variations: sects of Christianity, for instance, include Catholic, Baptist, Presbyterian, Anglican, Methodist, Lutheran, Mormon, United Church of Christ, Jehovah's Witness, etc. etc. etc. And sub-sects of these sects include Roman Catholic, Greek Orthodox, Southern Baptist, American Baptist, Mormonism (mainstream LDS version), Mormonism (cultish polygamous version), Mormonism (repulsive infant-torturing version), Church of England, American Episcopalian, Wisconsin Evangelical Lutheran Synod....
How do you know which one to wager on?
The differences between these gods and religions aren't trivial. If you obey the rules of one, you're guaranteed to be violating the rules of another. If you worship Jesus, and Islam turns out to right -- you're screwed. If you worship Allah, and Judaism turns out to be right -- you're screwed. If you worship Jehovah, and Jainism turns out to be right -- you're screwed. Even if you get the broad strokes right, you could be getting the finer points wrong. And in many religions, the finer points matter a lot. Taking Communion or not taking Communion? Baptizing at birth or at the age of reason? Ordaining women as priests or not? Any of these could get you sent straight to hell. No matter if you're Catholic, or Baptist, or Mormon, or Anglican, or whatever... there are a whole bunch of other Christians out there who are absolutely convinced that you've gotten Christianity totally wrong, and that you're just pissing God off more and more every day.