I have a horror of being That Guy Who Holds Up The Line. You know the type: the person in front of you at the checkout who waits until everything is totaled up, then begins the process of groping his flank to find his wallet, during which the ice cream you bought, which once had the density of the core of Pluto, has now liquefied entirely.

But now I was That Guy. The sign said I could get a free four-pack of orange slices if I bought two. I watched the clerk tote up the items, and when the third item was not reduced to zero, I said it was supposed to be free. The clerk froze. Unbeknownst to me, you see, some miscreant put mangoes among the oranges, and while someday we might live in a utopia where mangoes are discounted, we still live in an imperfect world of sin and toil.

The woman behind me in the line tensed and radiated spiky lines, because just her luck to get behind That Guy. I could have run back to get the right item, but once your purchases are being beeped you are locked in place, and the only way you can run back in the store without suffering glares and sighs is to hold the fruit aloft and shout THESE MANGOES ARE EXPLOSIVE — MAKE WAY!

"Cancel the mangoes," I said, having never said those words in that combination. "Sorry," to the lady behind, who nodded. Mango cancellation was the least I could do.

Left Target, went to Cub. Ten minutes later I'm at the self-checkout — behind THAT GUY. He'd beeped his coupon and put it in the slot, but something had gone horribly wrong, and he looked around, lost and bereft, palms up. I knew what to do. "Allow me," I said, and I blew gently into the coupon slot. Worked. He looked at me as though I was some minor deity whose holy breath could perform miracles, and possibly revive small dead animals.

"There's some kind of a sensor in there," I said, although I really wanted to say "just redressing the cosmic balance for the previous mango situation."

Everyone is THAT GUY at some point, in other words. Be kind. Even to the lady who doesn't start excavating through her purse for her checkbook until everything's beeped and bagged.

No, on second thought, don't. THAT LADY is the worst.