It is actually pretty rational to believe in God because, why not?
Which god? What happens if you believe in the wrong one and the real god ends up super pissed off? For all you know, the god you believe in might be an ex of the real god.
You might very well be worse off than if you had believed in no god.
Pascals Wager has been a discredited reason for believing in a god for a long time now.