Being a nurse is rough business - long hours, tough (and often disgusting) work, and little rest. Sleep is probably one of the hottest commodities for pretty much anyone who works in the medical field, and lack of it can lead to potentially critical mistakes in a job where lives are quite literally on the line. Mess with a nurse's sleep? You get the horns.

In this case, the offender is actually a nurse too - albeit one on a night shift schedule instead of day shift like the other roommates. This dude would be up at odd hours of the night being loud as hell in the ONE shared part of the house where the noise went into every bedroom, and it was getting old, fast. That's when one of the roommates decided to use classical conditioning - the kind made famous by Pavlov and his salivating dog - to train loudmouth into staying in his room at night. It required a few sleepless nights (which was happening anyway), but it worked like a charm!