Redskins head coach Mike Shanahan talks with cornerback DeAngelo Hall during last week’s preseason game with the Baltimore Ravens. (Jonathan Newton/THE WASHINGTON POST)

For more than 30 years, the Washington Redskins and their fans have witnessed an NFL anomaly that Mike Shanahan is in the process of reversing. Ever since George Allen left after the 1977 season, the Redskins’ coaches have fit a description that is seldom heard in professional football: Nice guys.

Well, that’s over. And about time.

One reason the Redskins look much improved in the exhibition season is that they are once again led by a dominant personality type that has often succeeded spectacularly in the NFL: a gloriously lopsided fanatic.

Look at the coaches who have won Super Bowls. One size doesn’t fit all. But what do about half of them have in common? Come on, you know. They’re not quite normal. And few ever described them first of all as “nice.”

When they sleep, you wonder if their eyes spin around in their heads (Tom Coughlin, Jon Gruden, Mike Ditka) or if they’ve been possessed by Satan (Bill Parcells, Jimmy Johnson, Bill Belichick). They’re so scary they’d make Gen. George Patton fumble his riding crop (Vince Lombardi, Don Shula). Or their icy stare says, “You, too, are expendable” (Tom Landry, Mike Tomlin, among others).

Would any other profession lend itself to such odd ducks — okay, besides science, law, politics, business, journalism, the arts and the military?

What’s remarkable is that any NFL team could have such a long run (1978-2009) of usually pleasant, sometimes funny, always sane coaches.

Jack Pardee was such a gentleman that the day he was fired and didn’t answer his phone, he was friendly when I rang his doorbell for an interview. Joe Gibbs I was plenty tough, Gibbs II a bit of a genial grandpa, but both versions were defined by virtues as much as obsession. Everybody loved rumpled Richie Petitbon, a superb defensive coordinator but a better candidate to be a Cajun Iron Chef than a head coach.

For years, Norv Turner was cursed with the Too Nice tag. Charming Steve Spurrier proved to be as much comic and golfer as coach. And Jim Zorn was so nice you wanted to scream — at him. The only exception was brusque Marty Schottenheimer. But an English lit major hid inside him.

To appreciate Shanahan, and not make fun of his bug-eyed death stare, you have to go back to Allen, the father of Redskins General Manager Bruce Allen. I once sat at a high school game with George and his wife. I expected an eccentric who drew Skins plays during timeouts. Wrong. He was relaxed, no stereotype in sight. But then, he wasn’t coaching.

Little in the NFL changes with the generations. Shanahan is a modern variant of the Allen prototype. If anybody ought to understand him, facilitate him and even mitigate some of his rough edges, it’s Allen’s own son.

Shanahan and Allen arrived in D.C. with chips on their shoulders, deeply slighted after being booted from previous jobs. And both illustrated the relative merits of fealty vs. raw talent in their pick of quarterbacks.

How can you choose Rex Grossman or John Beck to run your offense, rather than change your offense to adapt to Donovan McNabb? Easy. It’s happened before. And it can work. Allen always loved Billy Kilmer’s wobbly passes, and allegiance, more than Sonny Jurgensen’s spirals and individualism. Don’t say it’s impossible for a Beck, who’s bounced around, to take you deep into January. Kilmer, an NFL gypsy, started a Super Bowl.

George Allen brought in his Over the Hill Gang — players that other teams held cheap. They loved him, quirks and all; his schemes became their religion. Shanahan ensured his locker room authority just as fast — by systematically humiliating an insolent $100-million defensive tackle who was twice his size.

It took Shanahan 18 months, but he’s assembled his own my-guys cast: quarterbacks others have spurned, O-linemen who’ve been told they’re too small, and workaholics he believes crave precision and teamwork.

The issue with coaches who burn this bright and care this much is usually time: When will they burn out and who will burn up with them?

But such issues are likely to be well into the future. What the Redskins’ crisp August probably shows is that it’s time to bury the John Elway canard. After No. 7 retired, Shanahan managed a 27-24 record with Brian Griese at QB. He even saved a playoff spot with Gus Frerotte (4-2) as emergency starter.

From 2000 through 2006, Shanahan won 70 games in six seasons. True, he only won one playoff game. But those who doubt that Shanahan can turn a 6-10 team into a 7-8-9-win surprise, should look back at ’00-’01. Suddenly, 6-10 became 11-5.

There’s a case against manic men. Cowboys boss Tex Schramm once said: “The people I resent are the ones who try to give the appearance that nobody ever really cared enough about football until they came along. This is a terribly stress-filled business and you don’t have to make it worse.”

Maybe that’s a useful insight if your goal is to build a 20-year dynasty. But for years, the Redskins have suffered from too little of the proper kind of NFL stress. The kind that says: “Zero tolerance for sloppy execution, mental mistakes and no-show defeats against weak foes. Be ready, be prepared, every play, every game, or be gone.”

That’s not nice, not nice at all. But it certainly appears to be Mike Shanahan. Someday, it may wear thin. Right now, the Redskins and their fans are ready for a full adult dosage.