I carry a camera with me most places(often my Fuji X100S) and shoot a lot of street photography. About 8 years ago, I started forcing myself to interact with people I saw on the street to shoot their portrait. I love seeing light, being a fly on the wall and waiting patiently for a moment, but it takes an entirely different skill to approach a stranger and convince them to let you make a photo of them. I still see amazing looking people and fail to muster up the nerve to stop them.
When I passed Christopher on a sidewalk in Philadelphia I got nervous. He looked like a serious man in a hurry to get somewhere and I didn't want to bother him. Then the voice in my head kicked in as I've trained it to do: "Go back". So I did, and Christopher was a polite and flattered gentleman happy to have his portrait made with his vibrant red hat juxtaposed against the sprinkles of red in the background.