This is the best example for paying attention that I have ever
heard .

First year students at the Purdue Vet School were attending
their first anatomy class with a real dead cow. They all gathered around
the surgery table with the body covered with a white sheet.

The professor started the class by telling them, "In Veterinary
medicine it is necessary to have two important qualities as a doctor.
The first is that you not be disgusted by anything involving the
animal's body." For an example, the professor pulled back the sheet,
stuck his finger in the butt of the cow, withdrew it, and stuck his
finger in his mouth. "Go ahead and do the same thing," he told his
students .

The students freaked out, hesitated for several minutes, but
eventually took turns sticking a finger in the butt of the dead cow and
sucking on it.

When everyone finished, the Professor looked a them and said,

" The second most important quality is observation. I stuck in my middle
finger and sucked on my index finger. Now learn to pay attention. Life's
tough , but it's even tougher if you're stupid. "