I've noticed over the years my preferred focal length for street work has gone down. It used to be around the 85mm or 135mm, now I'm at 15mm most of the time and certainly no more than 50mm on occasion.
I believe it was Robert Capa who was attributed as saying "If Your Pictures Aren’t Good Enough, You’re Not Close Enough"
I'm of that school of thought now, my comfort zone with people is now much closer. I put this down to a few factors; age, experience, confidence and probably for me the most important; the ability to communicate with the folk around me and to become more involved and intimate with my subjects. There are some real characters out there, if you just take a moment or two of time after you've captured your image.