We all have our hobbies: mine is baseball caps. I have over 200 of them. There is no cap I own that, every day I wear it, provokes the response my old Montreal Expos tri-color cap does. I have literally never — not once — worn it in public and not provoked a smile, a thumbs-up, and the reaction of perfect strangers saying, “My gosh, that’s a great hat.”

It is a great hat. It also hasn’t been worn in many, many years. Even the latter editions of the Expos abandoned that hat. In 1992, they got rid of the red, white and blue background and went all blue backing the “M” logo — which takes a good long while before you notice it’s an “M” that actually also contains an “E” (for Expos) and a “B” (for baseball).

Tuesday, the team formerly known as the Expos and now referred to as the Washington Nationals will finally play a World Series game, something that was denied their Montreal forebears for each of the seasons from 1969 until 2004.

At the start, they were the pride of Canada, a national team whose early heroes were Rusty Staub and Ken Singleton and Steve Rogers; later it was Andre Dawson and Gary Carter and Warren Cromartie; still later Pedro Martinez and Larry Walker and Vladimir Guerrero. They came achingly close in 1981 — L.A.’s Rick Monday ended those dreams in the ninth inning of the deciding Game 5 of the NLCS. And in 1994, it was a labor war that ruined the greatest team the franchise ever knew.

It took 11 more years to kill off baseball in Montreal, a slow, agonizing death that included six out of the Expos’ last seven teams drawing fewer than 1 million fans (including 642,745 in 2001, when MLB threatened to simply eliminate them altogether).

They belong to memory now, even if the city of Montreal wants back in the baseball racket. They play in a different city and wear a different uniform (and the “W” logo on their cap is so disconcertingly similar to Walgreens’ it looks like they’re playing for the company softball team).

But, man. The memories. And that cap …

I asked Keith Hernandez a few years ago where the toughest places to play were, back in the day, and he immediately said, “Chicago and Montreal.” I asked why. He gave me a wry, sly grin. “Young man,” he said, “have you ever been to Chicago and Montreal?”

I have. I instantly understood.

If the Yankees had won the ALCS, you would’ve been inundated with stories about the greatest World Series that never happened, 1994. Yankees fans know the most recent player strike halted a season that ended with the Yankees at 70-43, 6 ½ games clear of the field, on pace for 100 wins.

The Expos were 74-40. That’s a 105-win pace. And they were on fire when the strike hit: 20-3 in their prior 23 games. It wasn’t just Pedro and Vlad, two Hall of Famers, and Walker, who may well get in someday. It was Moises Alou and Marquis Grissom and Cliff Floyd. It was John Wetteland and Ken Hill (16-5 that year).

“I cherish my championship ring from the [2004] Red Sox,” Pedro Martinez said early one morning in spring training 2005, when he’d joined the Mets. “But I should have two.”

The Expos had an absurd mascot. Its name was Youppi! (exclamation point included), which is pronounced “jupi” and is French for either “Yippie!” or “Hooray!” Youppi! had an orange beard and a furry orange body and is the only mascot to ever be thrown out of a game, in 1989, when one of his flying stunts landed him too close to Tommy Lasorda. Youppi! is one of only three mascots displayed at the Baseball Hall of Fame, alongside the San Diego Chicken and the Phillie Phanatic, rarefied company.

His jersey number was — of course — an exclamation point.

The Expos had two homes. Their first was Jarry Park, a single-deck beauty that sat only 28,456 fans and featured a swimming pool beyond the right-field fence and “usherettes” wearing mini-skirts who helped you find your seats, even in unbearably cold Montreal Aprils. It was replaced by Olympic Stadium, a hulking eyesore built for the ’76 Olympics that had a a retractable roof (which, it turned out, was unable to retract).

I spent a night of my honeymoon there (Expos 7, Padres 3), and you may say, correctly, my wife is quite an understanding woman. But, then, she’s the one who bought me my first Expos cap, so I would tell you she knew exactly what she was getting. Right from the jump.

Vive les Expos!