Before people leap on me I'm not saying all people are religious for these reasons or that all religions are about escaping these givens. Many branches of Buddhism, for example, are based on looking these right in the face. It is just a very good answer to the question of why sensible people might choose to be religious if you're looking for.

And personally I believe that very few people go through life without a few unjustifiable beliefs that help them not to look at this stuff too closely.