Tolkein said that it didn't pay to leave a dragon out of your calculations, if you happened to live near one. In the same way, it's a good idea to think very carefully about how God affects you, if you happen to live in a universe where He exists.

So the first question is, do you live in such a universe? Is He there, or not? Not "would you prefer Him to exist, or not?" Not "Does your culture say He exists?" But does He actually exist? Is He really there?

If He exists, this is a very different universe than if He doesn't. And it would be wisdom to live in a manner that fits the universe you are in...