I'll be driving at a safe speed and invariably, some jerk will be right at my bumper with his SUV or truck and flashing his high beams at me. When it is safe to do so, I pull off to the right so they can get past me. No sense inciting road rage over something like that.
A few years back, this happened to me on the Kancamagus Highway in NH. I let the guy pass me and then a couple miles later, I pass him because he spun out and slammed into a guardrail, wiping out his fender and one of his wheel axles. He wasn't going anywhere for a while. I just waved at him and kept on going.
Then we have the "Timid Tillies" in this hilly country, who will often brake going UP a hill, just when you need to keep a steady speed to get to the top. 20-25 mph in a low gear usually does it, but not when you are stuck behind one of these idiots. A mile of traffic can stack up in a hurry as most of them lack the courtesy and common sense to just pull out of the way and prefer to just keep spinning their wheels and blocking traffic instead.