"Old Pals" joke

Aging Gracefully...
Have you been guilty of looking at others your own age and thinking,
"Surely I can't look that old?" read on...
I was sitting in the waiting room for my first appointment with a new dentist. I noticed his DDS diploma, which bore his full name.

Suddenly, I remembered a tall, handsome, dark-haired boy with the same name had been in my high school class some 40-odd years ago. Upon seeing him, however, I quickly discarded any such thought. This balding, grey-haired man with the deeply lined face was way too old to have been my classmate. After he examined my teeth, I asked him if he had attended Sisler High school.
"Yes. Yes, I did. I'm a Spartan." he gleamed with pride.
"When did you graduate?" I asked.
He answered, "In 1961. Why do you ask?"
"You were in my class!" I exclaimed.
He looked at me closely. Then, that ugly, old, wrinkled son-of-a-bitch asked, "What did you teach?"