A story

Somewhere in the Chicagoland suburbs, a student was "pumping iron" at a gym on a hot muggy afternoon and was about to begin his final exercise. Before starting, he glanced at the weight on the machine, and, muttering to himself, said "That's too much; I won't be able to do that" and proceeded to replace the weights with smaller ones. Halfway into his routine, he found himself unable to finish the second set. Slightly annoyed, he stopped, a bit embarrassed by his overestimation of his own strength and, by the same token, the underestimation of his weakness.

After brief contemplation, he decided to further reduce the weight, but went when he went to do so, he realized that the original weight that he had originally perceived to be too much had actually been what he had been lifting all along. He had mistakingly taken the rack to be part of the lifting apparatus (and vice versa), and so he had mistakenly placed the smaller weights on the racks while placing the heavier ones on the machine itself. The student sat there momentarily reflecting on his mechanical incompetency, and, upon further evaluation, decided to finish up the last 1.5 sets without making any further changes, taking his time as needed.