I moved in with this spoiled rich kid about 2 years ago and got the distinct pleasure (more like torture) of living with him while his life went to shit. He was an only child and wasn't used to having to carry his own weight around the house. Like he would ash a bowl in the kitchen sink on top of people's dishes and just leave it there for someone else to clean up, and there were multiple times when other roommates and myself caught him stealing our food out of the fridge and lying about it afterwards.
But really his life went to shit when he got pulled over for speeding and the cops searched his car and found two vicodin pills in his wallet that he claims weren't even his. Since he had some prior shit with the law, he went to jail for the night and then got put on probation for two years. Before this, he was a miserable but tolerable stoner/homebody, but after he got on probation he couldn't smoke weed anymore and started turning more and more to prescription pills to make up for it. At first he was just taking lots of vicodin, then he started smoking oxy when he could find it, then the next thing I know our entire apartment is covered in pieces of tin foil with smoked oxy trails all over them and he's selling (and doing) heroin out of his room. He seriously had the sketchiest people coming through (one time he came back with a face-tatted gangbanger and literally boxes of shit they said were stolen from some house in East Side San Jose). This dude became such a strung out fuck that there was a whole month when I never saw him because he would get high in his room all day and only come out late at night when everyone went to sleep and he could have the living room for himself.
Then there was the time I had to tell his dad face to face that he was a heroin addict and dealer because he had disappeared for a week and everyone thought he was dead. Turns out he went on a six day bender sucking dick for dope in the Tenderloin before getting jumped and deciding that the street life was harder than playing xbox while your parents update your bank account, so he came back.
We were literally trying to kick him out for months, but our landlord said he couldn't because of some sketchy local laws prohibiting landlords from kicking people out when they have nowhere else to go. Anyway, we finally got him kicked out this January, and two weeks later our house got robbed.
Moral of the story:
Roommates are like Russian roulette. In my experiences, I've had 6 out of 7 roommates that were rad and I hung out with no problem and they made me happy I wasn't living by myself. But watch out because there's always that one that goes boom.