Couldnt resist from replying to this post.I was in the India Air Force...had also the opportunity to work with Army in many operations. I am an ex-NDA..and have done a few commando courses too. I am a trained fighter pilot (but went out of flying after a near-fatal crash) and an air-warrior. Left the services 4 years back.....at the age of 29.
I think civilians generally relate discipline to the defence services....rightly so, most of the times. However, the discipline what we as traders require is of the mental kind. Discipline, to me at least, signifies resolving the mental conflict...between (i) your need to do something that reduces your pain/fear (of loss...of leaving profits on the table...of avoiding a trade which 'looks' risky) or (ii) doing what is correct as per your trading regimen.
Initially it does require a lot of mental effort (to spot your faults and correct them instead of justifying them on the 'current global/local environment') to BE disciplined, but once you UNDERSTAND what you miss out by not being disciplined, discipline becomes your second nature. Then you dont have to 'be' disciplined....it comes naturally.
Thankfully, I had the opportunity of being a part of the services, but then anybody can have that discipline. A string of losses, and the pain that comes free of cost with it...can teach you much more than an Army life.
Just my views.....
Rakesh