An Engineer

I work in an evironment surrounded by very smart people (I call them “people with letters after their name”). Most of them hold a degree (or two) in one of the many branches of Engineering.
The popular phrase to describe Optimism vs. Pessimism has been adjusted in our case:

“The Optimist states that the glass is half full The Pessimist insists the glass is half empty
The Engineer explains that the glass was over designed”