I am a quite shy person ad often, when i find an interesting composition-subject (like a person doing something, a goup of people in a nice setting etc), i struggle to capture it because i feel like i’m being rude taking pictures without their approval, but at the same time i think that, by asking them, the spontaneity of the shot would be compromised. What’s your take about it?
Take the photo, don’t say anything unless they complain. It’s easier to ask for forgiveness than to get permission.
Seriously, if people are visible, and out in public they are fair game. There is no expectation of privacy. The only time I would hesitate would be if they are visible but on private property, like standing in their front yard. I also avoid taking pictures of children out in public if they are identifiable. Parents can be (and should be) very protective of them.
My reaction to people complaining is to show them the picture and be prepared to erase it in front of them if the confrontation gets out of hand.