I stood in line at a massive supermarket in Ohio. In front of me was a man with a mountain of groceries—boxes of cereal, three gallons of milk, bags of dog food, and frozen pizzas stacked like a brick wall.Behind him stood a tired mother holding a single bottle of baby medicine and a small loaf of bread.The man looked back, saw her holding the single bottle, and without a moment's hesitation, stepped aside and gestured to the conveyor belt."Go ahead, ma'am. You've only got two items."The mother smiled, said "Bless you," and placed her medicine on the belt.I stood frozen in the aisle.In my mind, a line is an absolute military formation. Priority is determined solely by order of arrival. To surrender one's position in line is to yield turf without a fight.Inside I said: THIS MAN HAS GIVEN UP HIS BATTLE POSITION. HE HAS COMMITTED A TACTICAL SURRENDER AT THE CHECKOUT COUNTER.But then I looked further down the row of registers. It was happening at cashier three. It was happening at cashier seven. People with overflowing carts were stepping back, waving people with single baskets forward.There was no law written on the wall. No security guard was enforcing it.It was a quiet, unwritten pact executed millions of times a day across the nation:If you have less, the tribe lets you pass first.When the man finally reached the cashier, I stepped up behind him. I had only a box of green tea. He turned around, noticed my tea, and immediately stepped back again."Go on, man. Just the tea? You're good."I looked at him. I did not move."I cannot take your place," I said with great weight. "You have earned this ground."He laughed, a warm, booming sound, and patted my shoulder."It's just tea, buddy. Go on before my ice cream melts."I stepped forward. I placed my tea on the belt.In this country, efficiency is not forced by rules. It is granted by strangers who decide that your small errand is more important than their big one.I paid for my tea, bowed to the man, and said, "May your ice cream remain frozen forever."He grinned and gave me a thumbs up.I walked out into the sun feeling lighter than when I walked in.