Mohegan — Goodwill, that everlasting intangible with no price tag, sure has its worth, whose residual effects were affixed to the faces of so many happy kids Monday night.

And it is nothing more than goodwill that inspires the folks at Mohegan Sun to keep opening their doors to the community. How fortunate indeed, that we here at The Day and GameDay get to be the vehicle that streams the kind of joy and memories unique to the high school sports experience.

Mohegan Sun, specifically Tom Cantone, the President of Sports and Entertainment, played home office to a new era in girls’ high school sports Monday night, rolling out The Day Volleyball Invitational for Lyman Memorial, Ledyard, Fitch and East Lyme.

The hope and wonder on the kids’ faces, the painted faces and signs in the student sections, the crowd in excess of 1,000 and the residual memories sustained this old quote from American entrepreneur Marshall Field: “Goodwill is the only asset that competition cannot undersell or destroy.”

That’s really what endures here: goodwill. A concept that feels in shorter supply now, what with the daily doses of shouting damnation at one another. And yet here’s Cantone, whose arena has been awash in Beyonce, Billy Joel, Springsteen, U2, LeBron James and Michael Jordan, sending this email to yours truly Sunday night:

“Tonight we have Hall & Oates,” Cantone wrote. “I hope they do a short set because I can’t wait to turn the room over for volleyball tomorrow night. Because if they go long, I can’t go for that.”

(A little Hall & Oates humor there.)

Imagine: Hall & Oates sold out the arena Sunday night and the man in charge was more excited for the kids arriving 24 hours later.

“Everyone won tonight,” Cantone said after the two-match event. “From the moment they arrived with big smiles to when they left, they will remember forever the night they played Mohegan Sun Arena.”

We here at GameDay are grateful for the hospitality. The crowd may not have been the biggest volleyball gathering in state history, but honestly, it’s hard to fathom more than 1,081 showing up any other time in any other place to watch a sport still making its way to the mainstream.

It was a helpful reminder for yours truly that sometimes, goodwill can be the entire point to an undertaking. I mention this because I arrived at Mohegan Sun in a rotten mood Monday night.

Let me explain: Marketing volleyball to the masses is not easy. If your kid isn’t playing, it’s doubtful you’re showing up to watch, even in a world class venue. We here at GameDay are all about goodwill, too. But then there’s also the concept of capitalism and Mark Twain’s belief that the lack of money is the root of all evil.

So I reached out to my friend Miranda Cahill, whose daughter, Annalyn, is a terrific player at Fitch and plays quite a bit in the offseason. I wondered if Miranda had contact information for various volleyball organizations in the region. Miranda hit a three-run homer.

In recent weeks, I and other colleagues here at The Day reached out to contact people at the six different organizations she suggested. One request: Please share the ticket link with your email list, which would be the quintessential target audience for this event. I reasoned that showcasing volleyball in Connecticut’s No. 1 entertainment venue for the first time was a big deal for the sport.

Neither I nor anyone else here at The Day or GameDay heard back from New England AAU Volleyball, NERVA Volleyball, The Sandbox, Sound Volleyball Club, South County Juniors Volleyball Club or Husky Volleyball. Not even an email back acknowledging they received the correspondence. Nothing. Zero.

And I’ve been steamed about this for quite some time.

I understand that common courtesy is swirling the bowl. But since when is a “thanks, got it” return email harder than ascending Everest in stilettos? I’m thinking one email blast from them to all their constituencies would have resulted in boffo ticket sales.

But then a funny thing happened on the way to staying in my snit.

The kids.

Peter Huoppi, the genius who makes GameDay go, noticed that some of the players caught wry grins just as they were about to serve because they saw their faces live on the jumbotron. Others sang and took pictures. All four schools brought lively student sections. A good time was had by all.

And the crowd turned out to be more than I/we expected.

Maybe it’s a lesson in learning to control what you can and sipping decaf in the face of all the rest. Or maybe it’s the necessary, yet comforting, lesson that goodwill is alive and well here in our corner of the world.

Up next at Mohegan: The Day Holiday Classic (basketball), Monday, Dec. 19. Notre Dame vs. East Catholic at 4, St. Bernard vs. Hand at 6 and NFA vs. New London at 8. Can’t wait.

This is the opinion of Day sports columnist Mike DiMauro