"Unless you are 100% convinced that no god/God exists, why not believe in a god of some sort?"

And, just in case nicodemusrat doesn't come slap you around for maligning the ethicality of atheism, BECAUSE INTELLECTUAL INTEGRITY MATTERS. And I say that on purely theistic grounds: I don't think God gave us brains so that we could ignore logic in order to avoid punishment.

There is no fear in love, but perfect love casts out fear; for fear has to do with punishment, and whoever fears has not reached perfection in love.
-1 John 4:18