Was riding on a local trail and came upon a guy walking his dog. He was in the left lane and dog in right lane. I slowed down and about 25 yards out I said passing on the left. He turned looked at me and started saying the F word a lot. Then said I was supposed to yield to him- I actually did come to a complete stop. I told him the rules of the trail- stay to the left, don't block trail,allow passing on the right and cyclists to slow down and give audible warning. we had a few words. I am a pretty big muscular guy(50 years old) and this guy was probably about 60 and obviously out of shape and fifty pounds less than me. I think he actually thought he was going to kick my butt so that's when I though the outcome would not be good so I got out of there.