Defining: Optimizer, Powergamer, Munchkin

[Moriato]

In my experience it goes something like this:

Optimizer = A word that munchkins use to describe themselves.

Powergamer = A word that munchkins use to describe themselves.

Munchkin = The word that everyone else uses to describe the people who don't think they're munchkins but "Optimizers" or "Powergamers" instead.