Years ago I had a roommate who took obscenely long showers. One time we were supposed to go food shopping but he wanted a "quick shower" before we went. I watched 2 episodes of narcos on Netflix, got frustrated, went shopping alone, drove to store, and did a week worth of grocery shopping, drove back, brought all groceries to the apartment (third floor), put everything away, waited another 30 minutes and he finally came out of the shower.

I have no idea what he did in there.