The on-ramp merges from two lanes down to one before it joins the highway. Just past where the lane divider ends, the car in the other lane, a car-length behind me, speeds up and pulls abreast of me to pass. Instantly indignant, I mash the gas pedal to the firewall, speeding up and wedging my truck into the ever-narrowing single lane I now co-occupied with my surprise rival. I pulled slightly ahead and the other driver gave up before we reached the highway proper.

As I merged onto the highway I was immediately ashamed of my behavior. I proved nothing. The other driver was certainly not humbled and educated by my insistence on proper merging etiquette.

What I had accomplished was to play the second riff in what John Murphy calls dueling banjos, the mutual, escalating, negative feedback cycle that ends in violence.

I hate it when I allow myself to attempt to punish what I perceive as bad behavior. For me, the temptation is strongest on the road. The impulse is very visceral in nature. I suspect it's strongly related to the not-well-understood phenomenon known as costly punishment.
Often, as in my vain attempt to revise merging manners, the "banjo players" are attempting to inflict on one another anti-social and pro-social punishment. That is, Ann sees Bob's behavior as anti-social, rude, or unfair. Bob may have the same impression of Ann -- or may just see Ann as a busybody who should mind their own business. Regardless, each decides that it's worth time, effort, expense, and/or risk to punish the other. That piece of music ends in tragedy.

Perhaps the reason why doesn't matter. It won't mean anything to a judge or jury if the escalation continues. All the behavioral economics in the world won't help my family understand death, permanent injury, incarceration, or a lengthy, expensive judicial ordeal. But for me, it helps to understand the roots of a behavior I'm trying to change. It helps me to see through the emotion, and substitute an alternative. The past few weeks, when I notice such behavior and feel a moment of indignation, I hum the first riff of dueling banjos aloud. Du-du-dum dum dum. So far, it's much easier to resist the temptation to strum out an answer.