Street photography isn't really my thing, but I try to do it from time to time.  The problem I have is that I am very shy about taking pictures of people without their permission, even though by and in large, I have a right to do so in public.  I find if you get permission, the subject changes and loses the look that drew you to the photo in the first place.

This is why I am always amazed (or cringing) when I see real street photographers at work.  I am just not as brave as these guys:

(video) Joel Meyerowitz On Street Photography

(video) WNYC Streetshots: Bruce Gilden