Maybe I shouldn't criticize as I've only been to one while sober. That was on a road trip to the Gulf of Mexico and we stopped somewhere in the middle of Alabama at about 4 AM. It was about 90 degrees outside with 100% humidity, and all the restaurant windows had condensation all over them. Inside it smelled like an indoor swimming pool for some reason. I went to take a leak and someone had left half their meal on the floor by the toilet via vomit, and the other half of their meal by the sink via ass blast. Actually, I can't really confirm if both messes came from the same person.
I went back to our table and said "We're leaving". I took a piss outside in their parking lot, then grabbed some snacks at a gas station and continued on our way. Fucking disgusting place.
I've eaten at a few in Columbus in the pre-dawn hours that may or may not have been in the same condition. I don't really remember.