Rationality

Yesterday, at the Economics department's Fourth of July cookout, I saw
a mosquito sitting on the leg of another student and sucking her
blood. I reached over and swatted it. She said, without any
hesitation, "Thanks, I didn't see that one. Those things always eat
me up."

It was not until several hours later that I realized that anything
unusual had happened. In most situations, it would be considered rude
to smack someone else's girlfriend in the leg. My action might have
been rewarded with a slap or worse. But everyone there instantly came
to the correct conclusion that I was simply exterminating an insect.