What made you choose your career?
Poor eyesight. Couldn't be a pilot.
Why go down that path?
If I couldn't fly 'em I would fix 'em.
What motivated you to this career?
Get to apply most of the esoteric lessons I learned in school. The relatively free travel and decent pay are nice too.
It may help if you imagine looking back on a career choice and feel that you actually accomplished something important to you.

