Getting in trouble while you're a young private, airman, or seaman is extremely disheartening. The first time you get hemmed up by your superior feels like you've let your entire squad down.
But there's an old saying in the military that rings true with experience: "No one stays in without getting a few Article 15s." Sure, maybe this doesn't apply to everyone, but you can take a bit of solace knowing that even your crusty first sergeant was once a young, dumb kid.
In fact, we think that being on the receiving end of a few ass-chewings makes you a better leader later on in your career. Now, this all depends on the severity of the infractions, of course — if you're constantly getting MP involved, then you might not see the rank of first sergeant, but a slap on the wrist can be a learning experience that our brown-nosing comrades are missing out on.
There's a plethora of mistakes a troop could make, but let's use being late to movement for the sake of picking a relatable example. It's something serious enough to warrant discipline and something sincere enough to be a genuine mistake. Word moves up the chain of command that you messed up and, at the moment you finally arrive, you're greeted by an ass-chewing.
If the NCO chews you out properly, you won't ever be late again. You'll feel the pressure of everyone else waiting on you. The disappointment of your peers is palpable. They'll let you know, with or without words, that this is your fault and it is completely avoidable next time.
Minor mistakes like these show a young troop that sloppiness has its consequences. You'll learn early on that failure is met with discipline — and this isn't nearly as bad as what could happen if the stakes were higher.
Another reason it benefits troops to get their stupid out of the way early is that they'll have first-hand knowledge of what to do with their eventual troops. It brings a sense of perspective that many of the goodie-two-shoed leaders don't have. You'll remember what is and isn't a punishable mistake and act accordingly.
Now, years later, you have to deal with your own troop who is late to movement. If you hadn't been late and suffered the consequences all that time ago, you might drop the hammer on the poor fool — or you could scuff them up like your NCO did and teach them the same lesson.
Not to sound all sappy, but everything really is a learning experience. It may take years to play out, but the perspective that getting discipline brings can actually help can make a great leader.