Then, instead of a crazy person, you look like an asshole.

Why do you care what other people think?

Seriously, just whisper and accept the stares. That's what I do. People lose interest in you after a while anyway.

I don't know about pavel_lishin, but I care what other people think because I don't want to be an asshole. I don't want to be the guy talking loudly on his phone on a crowded bus, because that's guy's obnoxious.

The guy who's whispering to himself is fine. Weird, but at least not an asshole.

Talking into a communications device at normal volume makes you look like an asshole? O_o

First, no one talks on the phone at a normal volume when they're on the phone. They always speak louder in order to speak "over" the noise of the bus.

Second, yes, it totally does. The guy loudly talking into his phone is audible to everyone on the bus, thanks to the fact that he's speaking loudly. It's really obnoxious. e.g. http://www.youtube.com/watch?v=O0uTi2qkgf0

With that said, you could probably practice this stuff on the bus without being obnoxious by simply speaking more quietly. You'll still be more annoying than the quiet guy reading a book, but probably not unreasonably so.