I got up early this morning and hiked about 2 miles to be on the side of a mountain early morning. I did two flights after 8am. Three ladies walked past me on the trail while I was there and another couple. We all said good morning etc. Then came along an angry older couple. They complained that they were bothered by the noise of my quadcopter and I was invading their privacy. I explained to them that if they were in my camera they would be about the size of an ant. I also apologized that I bothered them "twice" as I was packing up anyway. They continued to stand there like they didn't hear my first apology to the point where I asked them "I already apologized to you twice what more do you want me to do". I should have known what kind of people they were when the first thing they asked me was if that was illegal. When they were starting to walk off they said it should be illegal. I'm sure they complained to the state park ranger. I have flown my quadcopter all over california and arizona. All my encounters with people have been good ones until today. My wife thinks they needed a snickers and were grumpy early in the morning because they probably hadn't eaten.