Unclogged drain
The worst part about cleaning up a bathroom tub is all the hair that you find everywhere. Hair just falls off the body when people shower and can go into a lot of places. That is why it is important to at least try to clean up the bathtub once you get out, so as to not clog the drain.
Nobody wants to be the person that has to go in later to a hairy tub and almost throw up. On top of that, after a while, the drain will be clogged which means someone will have to clean it. We are happy to know that whoever it was got their sweet revenge on the rest of their roommates.