My whole family already knows what I'm going to write about from that title, and are already laughing. Be warned, math will be required for this story.
Some years back, we were all visiting The Wife's Mom, Jackie (about whom I have written) in Florida. The party included my Mom and my little sister, likely less than ten at the time. We all went to Universal Studios Florida. This was shortly after it opened in its full theme park form, and was...oh, let's call it struggling. They were offering deeply discounted tickets, and a free second day with each purchase.
The tickets cost $44.00 each. Jackie's current soon to be ex-husband Tom said he'd go buy the tickets. He wasn't going to PAY for them, of course - he told us all to give him the money and he'd go buy them. My Mom gave him her military ID card, saying it would get a 15% discount on the price. We all ponied up the cash, rounding off to 40 bucks each. He went off to buy the tickets, and we went off to enjoy the park.
As the day passed, Tom began to comment that we all owed him another four dollars each, as the tickets were 44 dollars, and not 40. We ignored him, as is out wont when dealing with him. He's the type of person that when they speak, you can't stop hearing a circus calliope in the background. He refused to stop; he began actively carrying on about the fact that he was in the hole for about twenty bucks, having kicked out the extra four dollars for each of us. He was told to shut up by the highest authority (Jackie), but he refused.
Finally, I lost it, and let loose with the most vicious arrow in my quiver - the truth. "Tom, my Mom gave you her ID card," I explained for all to hear. "At 15 percent off, that dropped the price of the tickets from 44 dollars to 38. I don't owe YOU four dollars, You owe ME TWO! Where's my two dollars, Tom?"
The look on his face was priceless - a combination of an old man trying to do ciphering without tracing numbers in the air with his finger, and the clear and sudden realization that he'd forgotten to use the card. He waved the whole thing off with a crotchety "Oh just forget about it!" and headed for a refreshment stand to get a bottle of water to pour over his throbbing head. The rest of the day passed without further incident.
The next day, we were all at breakfast, and as Tom went to the Little Curmedgeon's Room, the rest of us began recalling yesterday's incident with glee. I began doing a dead-on impersonation of Tom, demanding that everyone in the restaurant owed me four dollars. Everyone found it funny, but my sister Jennifer found it hiLARious - she was near loss of her excretory functions. When Tom returned to the table, we all calmed down and acted as if nothing has occurred. Except for Jen. She was unable to stop snickering, and couldn't look Tom in the eye. Every time he spoke, usually to ask what this kid was laughing about, she only laughed harder. Eventually we were all reduced to fits of giggling as Tom sat there in a cloud of befuddlement and ire.
Jackie's passed on, my Mom's passed on...Tom's still trucking along.
-EDIT - Except now he's not. He passed away this morning. I may lay four dollars on his grave.