PHILADELPHIA – The NCAA Tournament can be both cruel and exhilarating. Game days end with either emotion, there is no in between.

Carolina had a great day (or night) Friday, toying with an Indiana team that was seeded about right at No. 5. The Tar Heels combined the same dogged defense that has marked their late-season surge, more break-out shooting from Marcus Paige and a much-needed big game from Kennedy Meeks, who had to play 29 minutes because Isaiah Hicks fouled out in 7.

Friday was also another fortuitous day (or night) for Notre Dame, whose luck of the Irish has extended well past St. Patrick’s Day. The team that should be back in South Bend adjusting to the off-season pulled out its second straight improbable win, stealing the first Sweet Sixteen game from Wisconsin here on the final possessions just as it had done to stun Stephen F. Austin the week before.

Now Notre Dame has to figure out how to forget the 31-point thrashing from Carolina in the ACC Tournament 16 days (or nights) ago and somehow upset a team playing as well as any in the country and laughing along the way. With the corporate elite persona of Duke having a very bad weekend, the Tar Heels are allowing us to look inside at what is obviously a great group of guys that has found the keys to playing at a top level while having fun.

The first glimpse was last weekend in Raleigh when the Heels were ready to take the court for their open practice the day before the Florida Gulf Coast game. With a few thousand fans waiting anxiously in the PNC Arena, they let the walk-ons lead them out of the tunnel. Only the rest of the team held back, guffawing as the crowd got to cheer the so-called “Biscuit Boys” running onto the floor alone.

The ultimate practical joke came here a week later, and it became an instant Twitter rave when Theo Pinson crashed the buttoned-down NCAA day-before press conference with Roy Williams and his five starters. Pinson supposedly warned the guys he might do it, but even they looked a little shocked when Pinson appeared on the dais, draped his arm over a couple of teammates and said, “Where’s MY chair, where’s MY name tag?” Find any video floating around social media and watch the seated players look up at Pinson and then snap their heads to the left toward Roy Williams, who did not know about it but was hardly surprised. Grinning broadly, ol’ Roy said something like, “Now, you know what I have to put up with every dadgum day!”

A jolt of personality the program needed after an up-and-down season of perfect wins and puzzling losses. Now, thanks to the busted bracket so often the good fortune of other ACC teams, the Heels may be laughing all the way to Houston. They are a heavy favorite over sixth-seeded Notre Dame, whose coach Mike Brey allowed, “We need some guys to have all-time nights [but] crazy stuff’s happened . . .”

The truly crazy stuff happened over the prior 48 hours at the West Regional in Anaheim, when Mike Krzyzewski got caught with his Army bloomers down. After Duke’s half-hearted loss to top-seeded Oregon, Coach K was seen in the handshake line giving his presidential pat on the right chest to the Ducks’ Dillon Brooks, who had just dotted the “i” on the 82-68 victory by taking three giant steps the officials ignored and launching 30-foot heave into the basket as the Blue Devils waited for the clock and their season to run out.

Afterward, Krzyzewski said he was complimenting Brooks for being a great player but left out the part about “You’re too good to show off.” When Brooks revealed that and HD audio confirmed it, Coach K released a statement apologizing to Brooks and coach Dana Altman (who said he had yelled at Brooks to shoot as the shot clock expired). “I reacted incorrectly to a reporter’s question about my comment to Dillon,” Krzyzewski stated. The phrase “reacted incorrectly” was immediately added to Wikipedia and every other on-line thesaurus as a euphemism for “I lied.”

And to make matters worse, or funnier, Krzyzewski signed his statement, “Duke University Head Coach and United States National Team Coach” as if his standing with USA Basketball gives him the right to fib. How Nixonian of the noted Republican. Coach K’s handlers must have had the weekend off.

The entire game was bad news for Duke, except for superb freshman Brandan Ingram, who it turns out made the right choice where to spend his one-and-done season. With the rest of his team playing like, well, a No. 4 in the NCAA Tournament and ACC standings, Ingram continued to show why he should be the top pick in the NBA draft this June. The 6-9 kid from Kinston from the 7-foot wingspan was almost unstoppable and got much more of an opportunity to showcase his talent at Duke than he would have at UNC, where the experienced and talented Tar Heels are where they are by sharing the ball.

It looks to me like snippy sophomore Grayson Allen is also turning pro after going from the hero of the 2015 national championship game to such a petulant player than no other than Christian Laettner implored him to learn from his mistakes. The day (and night) tripper got almost a full-minute feature on the CBS broadcast, with clips of him leg-whipping various opponents this season. Allen blew off Brooks’ attempted embrace and left the court with a good-riddance glance. Hard to imagine him back at Duke with the personality transplant Laettner suggested.

And Kansas, the top seed in the whole friggin’ Dance, had a very bad night and lost to Villanova in the South Regional at Louisville’s Yum Center. You could almost hear the “Yum Yums!” echoing from Philadelphia to Chapel Hill.

Let the good days (and nights) continue.