There's always a few, and always will be. It's the same whether you're on a bike, or driving. I can't count the times (driving) where I've had to play leapfrog with drivers who insist on passing, only to slow down to a lower speed than I was driving in the first place.

When dealing with non-rational drivers, when I'm on a bike or in a car, I prefer to let them pass and move away in front of me. I prefer having crazy people where I can watch them than behind me where I can't. But, as a general rule (here), the nuts are a very small minority and days can go by without anything that I'd call an incident. Around here folks simply want to get where they're going, and don't have the patience to engage with strangers over nonsense.