Instruction is the closest many of us will get to upset recovery training (students DO try to kill you, though they dont intend to).
Hauling checks, or boxes or what have you, BY YOURSELF done long enough DOES teach you when to say when. (Your either learn or kill yourself).
Flying a Banderante, Brazillia, 1900, or Jetstream AS AN FO will teach you how an airline functions.
Being a Banderante, Brazillia, 1900, or Jetstream CA will teach you leadership.
THEN flying as an FO in a narrow body under a CA with twice your hours WILL teach you how to be an AIRLINE CA.
Oh, and by the way, all that time you have spent LEARNING how the real world works, will give you the b@lls to stand up to management when they try to force you into an unsafe flight. You will learn NO JOB IS WORTH ENDANGERING YOURSELF, YOUR PASSENGERS, OR THOSE ON THE GROUND!