That's probably where he learned the value of having smart, disciplined guys who were willing to be coached.
No different than any other endeavor or enterprise with a large group of people. If you have weak links, selfish/renegade types, people who don't believe in/follow the plan, your chances of success go way down. BB only takes guys who are willing and able to stick to the script and the moment you can't, you're gone.
His adjustments and game management are all top notch, but it's his ability to understand what value he can get from each player which results in the uncanny ability of the Pats to always be in the right place at the right time and know what to do, that sets BB apart from all others. He is by far the greatest coach in history.
This too. Choking under pressure is a natural human reaction and most football players and coaches are no different from anyone else. But BB is; and again, he seeks out the type of player who like him, can keep his head in the most stressful moments.