I love shooting candids, but most people become self-conscious if they see you shooting them. On a subway recently, I realized that if I used the shutter button on my camera's vertical grip, the people across from me probably wouldn't notice that I was photographing them. The noise of the shutter means this won't help in very quiet situations, although you can probably get away with one frame. So if you want to try it, make sure you get it right the first time.
San Francisco, CA