Approaching this guy was not easy...
I have lots and lots of stories. Like that one time when a random dude in a car did a serious U-turn to double-check why I shot his car.
Or a stranger I wasnt even aware of came to me and warned me, in a super aggressive way, that he will spend his entire life tracking me down abd do what needs to be done if I ever post his photo online. Drugs...
I had a homeless dude (one of the locals) go apeshit at me in a crowd.
I was taking pictures of the birds that will form in a V and cruise along the bluffs, not even people. People were actually in my way and pissing me off, stupid tourists.
I called him over and calmly talked to him. Showed him some of my photos (it was digital), told him if he was uncomfortable with me in the future to come and chat and we could delete anything with him if he wants. Dude didn't know what the hell to do with that and just shook my hand and walked away.
I have had less pleasant interactions as well. And always while NOT taking pictures of people. Like a fountain at a tourist town in Germany where a crazy lady started yelling at me. Or taking pictures of a little dog in a coffee shop (his owner knew and was good with it, we'd made eye contact across the room). It does make me worry more when I actually AM taking pictures and including people -- which is one reason I'm a terrible street photographer.
The dude when I was taking pictures of the dog was really passive aggressive. Kept saying "People think you're taking pictures of them" when he meant "Don't take my picture" but wouldn't just say it. kept hinting that I wasn't allowed to take ANYONE'S picture, even my new dog friend. When I told him what I was doing, specifically, he definitely didn't want to talk to me, just kept saying I shouldn't take people's pictures, "I'm just saying." So I yammered his ear off, told him my strategies for getting dogs to look at me, pulled out the phone and showed him pictures of other dogs I'd taken, and was generally really annoyingly friendly until he got sick of me and left, because screw you for being passive aggressive. My mom was catholic, so I can out passive aggressive you any day of the week.
Some people are just weird about shit. And that's coming from someone who is a terrible introvert who won't pose for a picture and far more likely to talk to your dog than to talk to you. You definitely have to have strategies. And read people to know which strategies to try. Sometimes you just need to stare at them with the dead eyes, other times you have to be so friendly they don't know how to be angry.