I might fear being wrong, if there was only one option, opposing atheism. But there are thousands different religions and orders of magnitude more mutually contradicting interpretations of their doctrines, so even if I am wrong - so is practically everyone else. If god's supposed to judge humans on the basis of what denomination they happen to belong to - atheism/agnosticism seems as good a bet as any other. And way more honest and humble than most.
"The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one." - George Bernard Shaw
