re: Why did God create such a gross digestive system in humans?

Well, it probably has something to do with our diet. If we ate fresh lean meat, nuts and berries like we were designed to, the clean breaks and ghost wipes would be in abundance.

But I like cheeseburgers and beer and brown liquor and after beer or brown liquor I make decisions like "Taco bell sounds amazing right now"

To further that point, if you have ever seen the dog eat something he isn't supposed to, you have probably seen him dragging his arse across the floor...