If the were a world wide flood, there would be a world wide sedimentary flood layer all at the same level. There isn't. Therefore, no world wide flood. There are many, many other impossibilitissues associated with the Genesis flood story, but the biggest unanswered question is where is the sediment layer?
If there is a god, I want to believe that there is a god. If there is not a god, I want to believe that there is no god.