You get say, one in 40 that are trouble makers by nature. The vast majority are there as they can use the combative nature to good use. And other skills, of course. There is almost one bad apple among a dozen or 2. And even then, only when they cause a person trouble. If they cause me no problems, I get along with them just fine. One example, Jerry Peterson, founder of Scars combat, had the fighting skills, and voluntarily enlisted in the military during the Vietnam War. He is reported to have killed four of the enemy with hands and feet and body, as it was too close to use guns. He said that him and his buddies, with hands tied, kicked their way out of captivity. He is one of those that knew where to use his skills for a higher reason. This is just something one can use when they need to. A lot of people ( after boot camp ) can have their own house and do their own thing , after work hours depending on what job one is doing. Other jobs have you constantly around others 24/7, so it can be hard to have any private time. I know someone in the Navy 20 years, they had their own rented house, off base, and after their 8 hour shift, they did as they pleased. Someone else I knew, had a job where they could get only 4 hours sleep. So it all depends on the job, and assignment.