Why are people so rude and stupid?

Okay, let's have a lesson in manners, shall we? Today on BART, a guy told me he was a rapper and wanted me to listen to his ipod to hear his "music" and buy his CD. The train was just about coming to my stop so I told him I had to get off the train. He in response said "I don't give a f**k if you're getting off here." Oh really??? You think it's okay to talk to people like that? Especially potential fans? It sounds like someone needs to work on his people skills if he wants people to buy his CD. And that doesn't include offering me a half-smoked blunt. And one more thing, to the rude rapper: the piece of cardboard you gave me that you took the time to cut and write your itunes address on is now in the garbage at my work. Haha, loser. -Bub