I would’ve been better off going chalk. Following Vegas’ lead. Or at least Nevada’s lead.

Instead, it’s time for my annual Yankees and Mets mea culpa.

Last year, I wound up overly pessimistic when I projected the two New York clubs. This year? Overly optimistic. I had the Mets winning the National League East with a 93-69 record and the Yankees capturing the first American League wild card at 88-74.

The Atlantis Reno sports book projected the Mets to win 88 games and the Yankees 85. That’s pretty good. If the Mets win their last three games, not impossible, and the Yankees prevail in three of their last four, less likely given the quality of their opponents, then they’ll hit their numbers on the nose.

So what went wrong for me? With the Yankees, it’s simple: Massive underperformance that couldn’t be mitigated even by the historically impressive debut of Gary Sanchez. With the Mets, it’s complicated, an unlikely mix of factors.

Let’s break it down, starting in The Bronx and shifting over to Flushing:

1. Alex Rodriguez. Remember him? Hey, at least he possessed the common courtesy to issue a warning last year with his terrible final two months of the season. Talk about foreshadowing. Talk about going from hero to zero. By dropping from 33 homers in 2015 to nine this season, he experienced the largest plummet of any major-league player (thanks, Baseball-Reference.com). If he had just met the Yankees halfway, with 21 homers, he could’ve joined the 700-homer club, probably avoided getting released and given the Yankees another win or two.

2. Mark Teixeira. He has delivered a few big homers in his final month as a big leaguer — none bigger than Wednesday night’s walkoff grand slam when the Yankees were down to their final out. Good for him for going out with some panache. Overall, though, his farewell year will go down as his worst full season. Just like with A-Rod, if he had split the difference between his excellent 2015 and his lousy 2016, the Yankees would be telling a different story.

3. Brian McCann. He needs one more home run to match the 20 that he put up with the Braves in 2013, the season that earned him a five-year, $85 million commitment from the Yankees. The difference? McCann worked as the Braves’ regular catcher that season. Now, with Sanchez taking over primary catching duties, McCann has transitioned to be the Yankees’ primary designated hitter. He needs to produce more to provide good value from that position.

4. Michael Pineda. He looked studly in spring training, trimmed down and ready to leap at age 27. Nope, just another tease. He pitched so poorly in the first half that he nearly earned a demotion to the minors. He looks better of late … but with one year before free agency, is there any reason to think he has truly figured it out?

5. Starlin Castro. Another guy who looked like he had it figured out in March, and man, during more than one stretch in his first Yankees season, Castro looked like their best player. In a year when performances by second basemen exploded, however, Castro ranked among the worst at the position.

1. Injuries. You probably didn’t need my help on this one. Jacob deGrom. Lucas Duda. Matt Harvey. Juan Lagares. Steven Matz. Neil Walker. Zack Wheeler. David Wright. Good Lord. Just imagine what kind of shape they’d be in if they hadn’t picked up Kelly Johnson, James Loney and Jose Reyes during the season, or if Robert Gsellman and Seth Lugo hadn’t emerged from minor league anonymity to save the starting rotation.

2. Hitting with runners in scoring position. If you rank second in the National League in home runs and 12th in runs scored, you’re doing something seriously wrong. Even with their recent uptick, their .223/.303/.369 slash line with runners in scoring position puts them dead last in the league in batting average and on-base and next-to-last in slugging.

3. Daniel Murphy’s signing with the Nationals. How would things have played out if Washington had succeeded in acquiring Brandon Phillips, the Plan A for second base? The Nats should send Phillips a luxurious thank-you gift for turning them down. Plan B Murphy, whom the Mets barely considered before trading for Walker, is an NL Most Valuable Player candidate, and his seven homers against the Mets marked his most against any opponent.

4. The running game. The Mets have surrendered 134 stolen bases, the most of any NL team, an indictment of both their pitchers — perhaps you’ve heard this is a particular problem for Noah Syndergaard — and their catchers.

5. The Jay Bruce trade. You saw what the Mets were thinking: “Hey, Yoenis Cespedes was an imperfect fit last year, and he worked out great! Maybe we can pull this off again!” Nah. Bruce, the trade-deadline acquisition from Cincinnati, has struggled profoundly and created more headaches than answers for Terry Collins’ daily lineup conundrum. Maybe he’s finally heating up after delivering big homers Tuesday and Wednesday — the first time he homered in consecutive games as a Met — but keep in mind that he has more conundrums coming with his $13 million team option (the Mets have to pick it up, don’t they? Even though they’ll have surplus if they re-sign Cespedes) and the fact that the Mets gave up infield prospect Dilson Herrera to get him.

Let’s catch up on Pop Quiz questions:
1. From Gary Mintz of South Huntington: Name the legendary Cardinals player mentioned in a 1967 episode of “The Andy Griffith Show.”
2. From Jules Posten of Morris Plains, NJ: What legendary center fielder appeared in a 1959 episode of “The Rifleman”?

In honor of David Ortiz’s pending retirement, Foley’s NY Pub & Restaurant this week is selling “The Sloppy Papi Burger,” a half-pound burger stuffed with pulled pork and dipped in barbecue sauce and coleslaw. A portion of the sales will go to the David Ortiz Children’s Fund.

Your answers
1. Stan Musial
2. Duke Snider

If you have a tidbit that connects baseball to popular culture, please send it to me at kdavidoff@nypost.com.