I've stayed in way worse. I went on a stag do in Brighton a few years back and couldn't get any rooms at short notice until I stumbled across one in Hove that had "plenty of vacancies". That should have been the first hint. When we were shown to the first bedroom the door was opened and two pigeons flew out. 2nd room when you sat on the bed the two ends of the mattress lifted up. The bathroom was the skankiest bathroom I have ever seen and that included public conveniences!
Added to the whole weekend though it has to be said, often gets remembered when we talk about the stag do. One other benefit is that I never get asked to book the hotels any more !!