The "angry guy" was having a fit down the sidewalk, as was his girlfriend. I think it was when I started using him as good example of the bad behavior of liberals, that pissed him off. When I said he was the typical irrational liberal who hates conservatives but can't articulate why, forming the basis for Ann Coulter's best selling book Slander, the guy charged.
People say he hit the megaphone with the book, but I don't think he actually did. He came extremely close, but the cone inside sits back just a bit. But he did, as Hillary would describe it, invade my personal space.