In high school we had a new football coach institute a weight lifting program. He would give out a t-shirt if a player attained a certain goal.

One of the goals was bench-pressing 250 lbs. After a number of weeks, many of the players had reached that goal, but Craig, one of the biggest linemen on the team couldn't seem to break the barrier, despite being a huge, muscular guy. One day, he came in late and wanted to try max 250. One of the guys said, "warm up with that bar, its 185." So Craig did an eight repitition warm up. Doing simple addition in his head was never his strong point, but he eventually figured out that the bar actually had 275 pounds on it.