But it's all worthwhile for the Patriots. Brady's teammates say every practice is like a game because Brady is so intense.
Source: Cover 32
After making the Super Bowl during the 2016 season, Brady stayed up until 1:30 A.M. studying the Falcons' roster.
He called his first game back from his Deflategate suspension "rusty." He threw for over 400 yards and three touchdowns.
When Brady was suspended for Deflategate, he couldn't be around the team. He apparently called up former Patriots receiver Wes Welker to play catch with him so he could stay sharp.
His emails revealed that he called ESPN analyst Mark Brunell a "Patriot hater" for doubting Brady's case in Deflategate.
There was speculation that during Deflategate Brady wouldn't take a lesser punishment because it would admit some sort of wrongdoing.
Brady said nothing relieves his anger like a good F-bomb tirade.
Read more: Tom Brady explains why he loves the F-word
If you're on time, you're late. Former Patriots Rodney Harrison said Brady goaded him into working out at 5:30 A.M. by saying "Good afternoon!" every time Harrison arrived at 6:30 A.M.
Source: ESPN
Brady once used "Joker! Rex Ryan, Rex Ryan!" as an audible call as a shot against the Buffalo Bills coach.
But don't taunt him too much. A college friend said Brady once leveled an opponent during an intramural basketball game because he was trash-talking Tom.
Source: Providence Journal
And former Patriot Dante Stallworth said that Brady would pay practice-squad players who intercepted him.
He has a healthy respect for good competition. Seattle Seahawks defensive end Michael Bennett said Brady compliments players who sack him.
And somehow, he keeps improving. Brady has worked to get quicker, and at age 39, said he was faster than he was coming out of college.
He also has a ridiculous diet that few others could follow. Avocado ice cream is a treat, and he even stays away from popular health foods like peppers, tomatoes, and mushrooms.
Brady micromanages his life to play at an age when others retire. For instance, he goes to bed at 8:30 to stay fresh.
Former Patriots quarterback Brian Hoyer said at a team dinner, after much convincing, Brady took part in a beer-chugging contest. "You couldn't have poured out the beer faster into a glass," Hoyer said. Brady just walked away smiling with his hands in the air.
Source: ESPN
Before afternoon games, Brady makes receivers prepare to stare into the sun by catching balls from the direction where the sun will shine during the game.
He's always intense. Don't ask Brady to play a game of catch: He'll drill the ball at you from 5 yards away, according to Brandon LaFell.
He doesn't take losing well. He admitted that he had to work on his body language so as not to be too hard on his teammates.
According to Bill Belichick, during a round of golf at Pebble Beach, Brady hit the ball onto the edge of a cliff. He went out onto the cliff to retrieve the ball while a caddy held onto him to keep him from falling hundreds of feet. Belichick was baffled by the move.
Source: ESPN
Similarly, Huard called Brady a "psychotic competitor," referencing a time Brady threw a backgammon board across the room because he lost.
Source: WEEI
Patriots receiver Danny Amendola said Brady once broke a ping pong paddle after losing to Amendola in a game.
Source: ESPN
Former Patriots backup Damien Huard said Brady once gave his teammates a pep-talk to make sure they wouldn't lose to a group of local firemen in a charity game.
Source: WEEI
Brady says he wants to play at least until his 40s — and he hasn't ruled out 50, either.
Source: ESPN
And when Brady finally got the starting job, he told his backup it was no sweat. "I'm going to be one of the best at this game," he said.
Source: ESPN
He told his high-school coach after getting drafted that if he ever got the chance to start in the NFL, the Patriots would never go back to Drew Bledsoe.
Source: USA Today
Tom Brady knew he'd be great. When he was drafted, he reportedly told Patriots owner Robert Kraft, "I'm the best decision this organization has ever made."
Source: MMQB
But it wasn't always easy. He hired a psychologist to deal with the stress of being the seventh-string QB when he first got to Michigan.
Source: ESPN
It started in high school for Brady. He used to have his high school teammates over his house to study film while his mom made them lunch.
Source: WEEI
Former Patriot Dan Koppen said that Brady is the most competitive person he's ever met.
Source: CSNNE