Visiting the dentist

I was sitting in the waiting room for my first appointment with a new dentist.

I noticed his BDS degree on the wall, 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 30-odd years ago.

Could he be the same guy that I had a secret crush on, way back then?

Upon seeing him, however, I quickly discarded any such thought. This balding, gray-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 St Mary's high school.

"Yes. yes, I did" he gleamed with pride.

"When did you graduate?" I asked.

He answered "In 1984. Why do you ask?"

"You were in my class!!" I exclaimed.

He looked at me closely.

Then that

ugly,

old,

bald,

wrinkled faced,

gray-haired,

decrepit,

muppet

asked:

Spoiler:

"What did you teach?"