Pull-ups are, without a doubt, one of the toughest exercises you can do. But they also provide the greatest benefits to your back and upper body.
As well as needing good upper body strength, you also need the mental strength to perform them.
I still used to hate doing pull-ups, and I hardly ever see anyone else doing them in the gym.
Even just 1 or 2 of these super compound moves are out of reach for a lot of people.