The vibe was obvious Monday night inside Madison Square Garden, outside the arena, on the television broadcast. The Knicks were playing the Celtics, and for one of the few times in the last quarter century or so, it was a genuine event.

“It’s a playoff atmosphere!” Clyde Frazier crowed on more than one occasion as the Knicks flattened the Celtics before one of the louder and more engaged crowds of the year.

It was. And whether it was a coincidence or not, the Knicks certainly seemed to play with an extra amount of pep in their step. The Celtics — banged up and safely ensconced at the top of the conference — maybe weren’t quite as intense, but then they were coming off their own playoff-level dress rehearsal two nights earlier in Philadelphia.

It was a wonderful night.

And also a melancholy one.

Because it brought to the surface the single-biggest issue plaguing the NBA right now. The truth is that nights like this are outliers during a regular season which increasingly feels way too long at 82 games. In an era of “load management,” when star players routinely show up in civvies on the bench as healthy scratches, it becomes an event when teams treat actual NBA games like exhibitions.

And it also serves as a reminder that the disparity between the regular season and the playoffs is as stark in basketball as it is in any other sport, and it’s not close.

The NBA playoffs are a two-month bonanza partly because of the stakes involved, but mostly because there is no taking a night off, figuratively and literally. So after six months of warm-up, once the NBA postseason begins, you finally see the world’s best players maximizing both their talent and their effort, two and three times a night depending on how crowded the TV schedule is.

This point really started to hit home a few years ago during the NBA’s bubble playoffs during the pandemic. Perhaps that was partly due to the games filling a three-month void, but there were so many epic performances night after night, game after game — specifically the Jazz-Nuggets series in which Jamal Murray (31.6 ppg) and Donovan Mitchell (36.3) exchanged haymakers across seven games.

If you love basketball, you especially love seeing it played at that level. And we get that every night in the postseason. We are grateful for the nights we get it in the regular season.

It’s a gaping chasm.

It’s different in other sports. Hockey is a wonderful case study. NHL fans believe with every ounce of their being that there is no thing greater than playoff hockey, and even if you’re a casual fan with only an occasional dog in the hunt, that’s often enough to convince you of that theory.

The thing is, hockey players are just different than most every other athlete. Even with the superstars, you get the sense they’d be delighted to find a frozen pond somewhere in Saskatoon and have at each other for a couple of hours with nothing more than a couple of kegs at stake.

So as great as playoff hockey is — and it is — you’re likely to get your money’s worth in January as well as June.

Football? Look, the regular season was already a grind, and it became even grindier with the addition of a 17th game. Still, though NFL games can be gauntlets of worry — one bad penalty, one ill-timed turnover and a season can come to a screeching halt — you rarely feel cheated during the regular season. Now, your team might not be very good — and a slog with a brutal team in the NFL is probably the most awful slog in any sport — but you’re never going to question the effort.

That leaves baseball, which occupies its own category altogether. Postseason ball is spectacular, and impossible to emulate across 162 games. Still, even at a time when 14 teams make the playoffs, the day-to-day matters. And if you are a true believer, it’s the grinds of May and August that make the payoffs of September and October so special. But if you are a casual fan? You know the difference between Game 5 of the World Series and game 73 of the regular season. It’s not quite as vast a difference as the NBA. But it does make a good rivalry series like Yankees-Red Sox or Mets-Braves that much more enjoyable.

And essential.

Man, IT really does make summer seem closer than it is just to watch Aaron Judge and Pete Alonso on the television again.

If you think the Giants are breaking the bank for Daniel Jones, ask yourself this question: Of the 32 NFL teams, how many have competent quarterbacks? Fifteen? Sixteen? If you believe you have one of them how do you not lock him up?

Impossible to believe it has been seven years since we lost Shannon Forde, the Mets’ trailblazing PR dynamo. Her spirit will forever be an essential part of the ballparks in Queens and Port St. Lucie.

When the Celtics are playing Game 7 of the Eastern finals in Milwaukee instead of Boston, do you suppose they are going to remember the way the Nets ransacked them after spotting them a 28-point lead Friday night?

Jim Moon: Does the NBA have a rule not allowing the Knicks and Nets to be good at the same time? It’s almost comical how this non-rivalry rivalry keeps flipping on a dime. Only good memory I have is Ewing-Derrick Coleman series in the ’90s.

Vac: I think the rivalry peaked 30 years ago when John Starks broke Kenny Anderson’s arm. It is amazing.

John Cobert: The pitch clock seems to be eliminating all the “dead” time just fine, but I don’t think the beer vendors will appreciate shorter games and fewer sales. Look for a price increase.

Vac: I always half-expect beer prices to go up three yikes while I’m at a game, so few things surprise me there.

@knishboy: I’m inviting Julius Randle to be the guest rabbi at my kids’ Bar Mitzvah.

@MikeVacc: I would say Julius’ redemption tour is complete, wouldn’t you?

Howie Siegel: I think I see a potential TV series in the works for the Grizzlies’ Steven Adams. Perhaps something about his Life and Times?

Vac: If you’re old enough to get that joke, both Howie and I thank you very much.