I agree with springely's answer. When people keep trying to convince others to stop feeding the troll, he only gets encouraged because he knows it bothers so many people. Personally, I can't be disrespected if he doesn't even know me. I just let it go and pass by.
Well yeah. I mean, It'd be kinda stupid ( no offence) to take him seriously. Since he's here might as well make the most of it and screw with him a little.