Being nice does NOT always pay...

So my best friend is dating this guy (we will call him B) okay.... I liked him at first. About a week and a half or so ago, they stayed the night. Well, the next day B's car breaks down and he has to stay here for a few days. Well he preceded to tell my husband and I about his nasty living situation with cockroaches, and dog and cat poop and pee everywhere. In all fairness, he's actually a neat freak so it's not him... it's the people he was living with. So Sam and I decided that he could live with us under two conditions. 1) He doesn't bring pot into the house. 2) He doesn't smoke pot while he's trying to find a job. What happens? My best friend and him both go to a party and he smokes pot. Now, I don't have a problem with people that smoke pot, as I used to be a pothead myself. It's just the fact that he broke the second rule, thus proving that he has no ambition what-so-ever to find a job. Not only did he do all of this but 2 or 3 days before that he was working on his car and when he was done, HE POURED MOTOR OIL DOWN OUR FUCKING SINK!!!!! I mean, seriously, who the fuck pours MOTOR OIL down a sink?? You can't even pour cooking oil down a sink without running LOTS of cold water down the drain with it. I swear, everytime I do something nice for someone (because B living with us was my idea in the first place) I end up getting kicked in the teeth.