My kids play football and cheer and we were at the Mid-America Little Scholar Banquet last year for Pop Warner. The keynote speaker was a former player (current dad and coach for a PW team) who played with Brady on the Patriots in the mid-2000's. He explained to the kids at the banquet that Tom Brady's success did not just happen - he said that Brady was the first one in the weight room/meeting room every morning, and the last to leave. He never took a rep off, or a day off, or a play off. He talked about how many hours of film Brady and the team would study each week, and how they ran practices like it was a game. He talked about the expectation the coaching staff had of the players, and vice versa. The Patriots system is a system of belief - belief in the way they do things, how to behave, how to act toward yourself, your coaches, your teammates, and your fans. These players buy in to the system, and it shows. That's why they can change wide receivers and other positions every year and still get the same results.
I'll never forget some of his final words to the kids: "Players who look for the praise and glory on the big play don't do well in New England."
Sums it up perfectly.