Meeting with anger seems to be one of the unavoidable risks of doing street photography.
Over the many years that I have done street photography, I remember three assaults:
One was while I staid in Goa, India. I pointed my SLR at a young man who very quickly began to get agressive, even to the point that he suddenly had a knife in his hands. I presume I focused on some dropout drug addict or thug who didn't want his photo taken, or this person was mentally deranged. I resorted to run, and I was fast.
The next incident happened in my home town. I had just bought a rather largish wideangle zoom lens for my DSLR, and I wanted to test it on a very crowded square in downtown Munich. I hadn't even started to take a picture when a young man started to shout at me, warning everybody near me that they might be pictured. I guess he was just plain sick. I walked away without further consequences.
The third time was the scariest, as it apparently happened without any clear cause. I had my DSLR with a 200mm tele lens, and I was taking pictures of some old men playing chess on a public square, when I was suddenly surrounded, shouted at and bullied by a group of five or six young men and women. Quite clearly, they objected to my taking pictures, although I had never pointed my camera into their direction. Since I was near a street cafe with some 200 potential witnesses, I started to yell so that people would notice the threatening situation. Also, I was preparing to defend myself - my camera with that massive lens would have been heavy enough to seriously hurt someone if need be. Fortunately my yelling and determined, yet defensive behavior obviously raised the stakes too high for my attackers, and they let me go. But still, I don't know what motivated them to become so agressive.
Summary: Use a small, unobtrusive and non-threatening camera, be courteous and friendly as long as possible, but also be prepared to either flee or fight. I'm a rather big guy, so I don't get scared easily, and I know I can defend myself if need be (Up to now, it has never been necessary). So, I haven't lost the thrill of photographing on the streets.