A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

A person who doesn’t utilize the skills/brains/charm they are perceived to have (by others) is usually referred to as “underachiever”.

In informal, spoken AmE, the most common equivalent of “on the contrary” is the word, bullshit :

The salesman assured me that the suit was black; bullshit, it was navy blue.

That would be useful, in your construction: The casual

encounters didn’t work for me, though. It was bullshit – (Yes, the singular “IT”) each of them left me emptier than before, made me feel guiltier than before.

It’s crude but widely used and accepted. (US)

(People) (English) (Britain) (English) (US)