What job would you do on a starship?
If you were given a commission on a starfleet vessel, what job would you want to do? You can't be Captain or first officer as you would have to do something else to earn the rank.
I think I would be an engineer. Mainly because I like problem solving and they always seem to be in the thick of the action.
"Unless you have something a little bigger in your torpedo tubes, I'm not turning around!"