It is polite to clean up after yourself in public
Adam is using the bathroom in a big box store because he has a bad case of the runs.
Adam doesn't want to draw attention to himself.
Adam takes the time to clean up after himself to avoid people knowing he messed up the bathroom.
Adam leaves the bathroom as quickly as possible to avoid notice, leaving behind a huge mess of crappy toilet paper.
The custodian has hardly any mess to clean up that afternoon.
The custodian has to put the bathroom out of order while cleaning up the mess.