One of the kids needed a blanket picked up from the floor in the backseat of the car. Sara and I both reached back to get it at the same time, me with my right hand, her with her left. Our elbows bumped, so we both pulled our arms back to allow the other person to reach back. Seeing that the other person was not going to reach back, we both reached back again, bumping elbows a second time. We both pulled back, this time determined to wait and allow the other person to reach back. Eventually, I gave in first and reached back. This time we did not bump arms.

Me: “You know what we just did? Collision detection with random backoff. Like ethernet!”
Sara: “…”
Me: “If you knew what I was talking about, you’d totally agree.”

I’m telling you, they should use that like a story problem in textbooks. It’s the perfect example! Next time you use the Internet, think of my elbows.