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The story goes like this: One practice, Bill Parcells, while coaching the Giants, got into an argument with the best linebacker of all time, Lawrence Taylor. It was heated. Then more heated. Then, it got physical.

Eventually, and incredibly, the two men ended up on the ground, scuffling and wrestling, until the fight was broken up. This happened in front of the entire team. Players watched incredulously. Taylor was 6'3" and 240 pounds of steel. Parcells, well, wasn't. Imagine seeing that. Imagine if that happened now, in the Twitter world.

Both Parcells and Taylor are in the Hall of Fame, and years later, Parcells can chuckle about the fight. What was most important about it was the two men followed the cardinal rule of football fights: Put them behind you, don't let them fester, don't let them destroy the relationship. They would repair the damage, even have more fights, but the fights never drained their closeness and desire to be unified.

"I loved him like a son—and still do," Parcells said in an email to me, confirming the incident. "But we had a couple of scuffles. But no matter how bad it was between us, he always stood next to me on Sunday for the national anthem. That was his way of telling me he was with me. We were still pals."

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In the NFL, the greats—like Parcells and Taylor—when they fight, they let it go. The smart players, the smart coaches, they let it go.

Fights during NFL games and practices have been around for decades, maybe since football's beginnings. Some of the stories are as entertaining as the games. There's been player vs. player. Coach vs. coach. Player vs. coach.

Recently, there was this fight. And this fight. And fights on top of fights on top of fights. There was once even a fight on an airplane.

Some fights are even orchestrated. Before Parcells' Giants played Buffalo in the Super Bowl, the Giants coach was concerned about a lethargic practice the team was having. So Parcells had an idea. As the Star-Ledger's Jerry Izenberg relayed, Parcells called Taylor to the sideline and asked Taylor to start a fight. Taylor punched 300-pound Jumbo Elliott, and Parcells got his fight—and a better practice from that point on.

The difference between those fights and what happened this week with the New York Jets is that most fights happen on the practice field or inside a stadium during a game (fight on the aircraft aside). That's why what happened between Geno Smith and IK Enemkpali, where Smith had his jaw broken during a locker room clash, is so unusual.

One seven-year veteran told Bleacher Report he's never seen a locker room fight—or even witnessed teammates upset enough to get into one. Fights on the field? Yes. Locker room fights? Almost never.

That cannot be emphasized enough. Locker room fights are rare. Injuries from locker room fights are rarer. Injuries from locker room fights are equivalent to a Bigfoot sighting. A severe injury, like a broken jaw, from a locker room fight is like seeing Bigfoot on the hood of a UFO. A star, the quarterback, missing a month or more because of a locker room fight is like seeing Bigfoot land a UFO on Atlantis.

Raiders offensive lineman Donald Penn told San Jose Mercury News columnist Tim Kawakami that what happened to Smith wouldn't happen to his quarterback, Derek Carr. "That would never happen here," Penn said. He also noted, "If someone did that to Carr, they'd have to see me next. And then probably the rest of the O-line. That would never happen here."

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Raiders coach Jack Del Rio was asked about the Jets incident, and his answer echoed those of other players and coaches interviewed for this story.

"I hope we don't have anything like that going," Del Rio said Wednesday. "We are human beings. Human beings sometimes make mistakes but we certainly don't want to see that."

Del Rio, who was a player in college and the NFL and is on his second head coaching stint, was asked if he's ever seen anything like that. Here's what he said:

Not quite with the quarterback. I mean, I've seen guys get in fights before. Things happen. People have disagreements, sometimes they're not able to settle them peacefully, and aggressive men—sometimes it can go the wrong way. But our guys have been great. We're learning how to practice against each other. I think they're being very competitive, but we're taking care of each other. We want to challenge each other and compete in everything we do. We want to be respectful of what we're all really here for, what this is all about. ... I just can't imagine anybody feeling that way toward Derek, so it's just a shocking thing to see from afar.

What we've learned in the several days since the fight is that the Jets violated the cardinal rule of football disagreements: Patch things up, or they will get worse.

That is, in some ways, a life rule. But it is extremely important in a violent team sport like football, where testosterone levels and egos are stratospheric, and where cooperation and closeness are key.

"Fights on the field happen," veteran Jay Feely told me. "That's where they need to stay, or they fester."

Two different Jets team officials confirmed what former player Ryan Clark, who knows Enemkpali, said on ESPN's Mike and Mike this week: Smith was supposed to attend a camp for Enemkpali, and Enemkpali paid approximately $600 for a plane ticket. Then someone close to Smith died, and Smith couldn't attend the event.

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About $3 million of Smith's rookie deal is guaranteed. He could afford to pay back a $600 ticket. But, those sources explained, he refused to and then, several months ago, basically told Enemkpali he'd, as one source said, "pay him when he paid him."

And there's the festering part. The two didn't squash the beef, and it lingered. That led to the violent confrontation and Enemkpali's ouster from the team. They broke the first and only rule of NFL fights. They let the disagreement linger.

I'm told by several different team and league sources that head coaches across the sport are using the Jets as a teachable moment. (Though the Jets teaching anyone anything other than how to provide comic relief is frightening.)

The coaches will likely be sending similar messages: When it comes to arguments and differences and fights, put it all behind you.

If that doesn't happen, then the punches might keep flying.

Mike Freeman covers the NFL for Bleacher Report.