Its a tie for my job. I work in manufacturing with ages from 17- late 60's or early 70's. We had one who was 17-18 still in high-school. He would argue with anybody about how to do the job. When he argued with me (I have been in the trade for about 5 years) and thought okay I am one of the youngest guys in the shop. Then he said somebody else was wrong. He had been in the trade for 12 years. Okay maybe the kid is trying to prove a point. Then he said the supervisor was wrong who has been in the trade for 30+ years. That's when everybody just told him what to do and wouldn't let him talk back. He also couldn't lift more than 30 pounds by himself. Its a shop where you should be able to lift about 80-100 pounds up to shoulder height.
The second one is a guy a few years older than me. When I got hired in I was fresh out of the military and they told me he was a military veteran too. I thought cool someone who will understand my jokes and stuff. Well he couldn't do any of the stuff he claimed he could in his interview. He worked there two months before me and I surpassed his abilities in the first month. Turns out he was a reservist (which he lied about in the interview) and got kicked out of the military (which he also lied about). I always found it strange he would ask really dumb questions about the military like what a purple heart was and the medal of honor. He thought the medal of honor was something you got for being good at something. He claimed he had two. I corrected him. But it seemed like he was atleast trying to learn the job even if he failed a lot. In this shop you have to buy your own tools after the first three months. Well one day the supervisor is helping him learn a new job and says "I think its time you start buying your own tools." Now our supervisor is known to be a jerk sometimes but he wasn't this time. This guy got mad like how was he supposed to know. He just left. Never told anybody he quit or anything. He left his coat and hat and cordless drill at the shop like he was coming back. Well three months later he comes back in his work shirt like nothing happened and asked what he was working on that day. The supervisor just told him nothing since he doesn't work there anymore and the guy got mad and stormed off leaving his coat. He had to make a walk of shame to get it and had to be escorted by myself and a beefy looking guy in case anything got heated. He never came back but we were expecting him to be waiting in the parking lot after work. Yeah fuck that guy.
TLDR; one kid was never taught to respect people and the other was just an idiot.