Evil is the extreme end of cruelty for cruelty's sake. Annoying your 10 year old brother is cruel, but fun--probably not evil. Punishing people for eternity, or exterminating a race of people is evil. Somewhere closer on the scale to annoying your brother than punishing people for eternity is wrong, but not evil.
If there is a god, I want to believe that there is a god. If there is not a god, I want to believe that there is no god.