Why do some teens actually try to give the rest of us a bad name?

I just went to pick my sister up from work, and when I got there, a truck and a Caddilac were circling the building, and they were honking and shouting obscenities from the windows, while there were small toddlers and their parents trying to leave. I asked my sister how long they had been doing that, and she said they had been out there for a while. Why do some people do this and give the rest of us bad names?