There is a God. So what?

Assuming there is a god, it’s probably arrogant for us to think we’ll understand it, its intentions, etc.

Knowing that, is there any difference to think “What does god want me to do for myself” than thinking “What should I want to do for myself”? Do you really think that god would give us an instruction book for how to live, when learning in any case is better when you’re left to do it on your own?

So if there is a god, why should it affect your life?