I've already posted my roommate horror story from my freshman year... but I have a roommate horror story from my husband.
During his first year of grad school, he lived in an apartment building designated for single first-year grad students. Each apartment contained 2-4 bedrooms, a kitchen, and a bathroom, and the larger apartments had a common room. All apartments were single-sex.
My husband (then-boyfriend, though we got engaged during the year) was assigned to a 4-bedroom apartment. Two of his three roommates were hardly ever in the apartment and mostly kept to themselves when they were there, so no problems there.
Then there was "Larry".
Larry was returning for a graduate degree after serving in the armed forces, so he was about 30 (everyone else was 22-23). He was always around the apartment because he had no life. He was loud and boisterous.
Larry also had the world's worst B.O. We called him "Smelly Boy" behind his back, and joked about how he needed a visit from the Right Guard Fairy. I learned very quickly that if I stayed overnight and Larry took his morning shower before I had a chance to do so, I was best off going back to my own dorm and showering there... in fact, my husband came with me to my dorm to shower, more than once. (I was still an undergrad, same school.)
Larry sold Amway products for some extra cash. (In his favor, I will say that he never tried to pressure me to buy anything.) He bought a lot of Amway products himself, including their food. I suspect that he had B.O. (and, btw, was grossly overweight) partly because all he ever ate was preprocessed food from Amway.
The following year, my husband and I got into married student housing (even though we weren't married yet) and we haven't had to worry about roommates since.
