I used to ride the public bus a lot, like 3 hours every day. So maybe the thought that some dude somewhere said something crazy is less exciting to me than it is to people with less bus-riding expertise. My advice? When the person you are going to have to sit next to for the next hour and a half is obviously batshit insane? Talk about the weather. I have been exposed to the full, glorious panoply of mental illness and brain damage in my time on public transportation, and I have yet to encounter anyone so far gone that they can’t be calmed by polite small talk about the weather.Amen. There's nothing like being trapped on a bus with at least one nut or crackhead or drunk a couple times a week to desensitize you to crazy talk.
I did once encounter a nut who was immune to smalltalk about the weather, though. We were waiting for the bus (not the same bus, thank goodness) in Arlington, VA. He was 100% sure the air in Arlington was "bad," and he needed to get to Fairfax (the next county over) as soon as possible. The only reason he was able to survive in the Arlington air was because he had a snorkel duct-taped to his nose. I know this because he explained it, in sputtering sentence fragments and at the top of his lungs, over and over again. For added security, he'd blow a whistle really loudly every couple of minutes.
I think he's a deputy secretary over at DHS now.