The services can give the young folks the ability, thru the extreme structure, the ability to structure themselves. How many times have you stood behind a kids and shown them how to do a knot? That is how extreme control and structure sometimes work when nothing else does.
The pile of skills you learn plus you also learn to think like a possible enemy. The key is to remember why you came, and what your goal was. You learn to work within a very structured environment to get what you want and what needs done. Those rules do not necessarily apply outside the service, but it does teach you a cause and effect for your actions.
You pick up crude camping skills, marksmanship, a trade if you pick the right MOS, stress management, how to deal with the lack of modern convenience, learn about the world beyond the USA in a manner tourism will never teach, etc.
Meantime the entry tests during the schooling phase are a lot of fussing and bullshit. A 2 year tour of duty was mainly training up a bullet throwing bullet catcher, a war in some far off place, and a month or two while the processed your walking papers. Now it tends to be a year of training, 2 tours of duty in some far off place, sometime with lead weighted weather, and a process for discharge.....oh and it is a voluntary trauma thing, probably no worse than jackass the movie.