This morning I was flying over a pond at a local park. I was the only one there when I started and there were maybe a half dozen people feeding the ducks off to the side of me by the time I left. I was 15 minutes into my flight or so when I hear someone yelling "keep moving/flying motherf----r". I look down and some guy walking a couple of dogs is looking at me. I looked back to my FPV and he kept rambling, the only other thing I could make out was "I'll break that" or something to that effect. He eventually wondered off. I didn't look at him again or make any acknowledgement that I even heard him. My glance at him was so quick I couldn't even tell you about what age he was. I'll have to check my video later, maybe he's on it. I just checked my telemetry and I was 90 feet up at the time, so I can't imagine him thinking his life was in danger? I may have slowed down somewhere close enough to him that maybe he thought I was purposely making a video/spying on him? Thus the "keep moving" comment. I definitely wasn't as the first time I even realized he was there was when he started yelling. Was I being reckless in some way or was this guy just a drone-conspiracy nut? I was flying very gentle and slowly, I wasn't zipping around trying to show off or anything. I was particularly careful since it was a public park, although there were hardly any people around (and I never flew overhead of anyone). I was even careful not to freak out the ducks—for the record they didn't seem to care about the Phantom at all.