I have no word for this...

He must be a real pro.

OCD? Dyslexia?

I don't get it

I have two words.... Ell and Ar

Maybe he never learned his left and right hands

Must be fun to activate left-handed mode for that mouse.

Will they:
A) Figure out the trolling
B) Swap the button labels
C) Get a new mouse
D) Collapse under an existential crisis caused by the underlying shift in their cognition of handedness

You can even start an office betting pool.

The labels should at least be primary and secondary.

Although I do use my mouse left handed and right click by pressing the left button.