I am, at turns, amused and exasperated by sports gamblers.

How can they participate in a system in which the “house” never loses? How do they convince themselves that they are smarter than most other gamblers?

How can they witness how totally random NFL games (well, just about any game ever played) can be?

Take, for example, the Minnesota-New Orleans playoffs game last week when nearly every point-spread bet was influenced by the bizarre ending of the game?

If you do not recall …

The Vikings got a 61-yard touchdown pass on the last play of the game. They had been trailing the Saints 24-23, and Case Keenum chucked the ball up about as far as he could fling it, and Stefon Diggs caught it, then watched as a Saints defender took himself — and a teammate — out of the play … and turned around and sprinted to the end zone.

Bedlam.

Except in gambling dens, where things had gotten very weird for just about everyone who had bet on the point spread.

(Hang on. We will supply video of the chaos at the end, further down.)

The point spread closed, at most Las Vegas books, with the Vikings favored by 5.5 points.

When Diggs scored and everyone ran off the field with “29-24” on the scoreboard, everyone who bet the Vikings at 5.5 was a loser and everyone who took the Saints at minus-5.5 was a winner.

Then there were those who bet during some of the gyrations in the line, ahead of the game. There were instances of the Saints getting only five points, and apparently some other books had them getting six.

So.

If the game ends with the teams off the field, which looked like the case for at least 10 minutes of chaos … All Saints backers won, aside from those who took them at minus-5 — which became a “push” — everyone gets their money back. (Same for Vikings backers of the plus-5 line.) No harm done.

Then, it became clear that the NFL has a rule requiring the scoring team to line up for a PAT, even when it does not affect the outcome of the game.

Most people, including gamblers, assumed the Vikes would come out and kick a PAT — and that would change life for everyone.

The Vikes would win 30-24, and the Vikes plus-6 guys had a push but the plus-5.5 and plus-5.0 people were now winners. It was the other round for Saints backers, if the Vikings added a point: Those who bet the Saints when the spread was 6.0 would have a push, and everyone else at 5.0 or 5.5 were now losers.

Following this?

The teams finally were rounded up, and the Saints were so disinterested in hanging around for this event that the idea of anyone blocking a kick and returning it for two points was really, really unlikely.

But it didn’t matter because … the Vikings took a knee. No extra points.

That’s where you can see the reaction at one sports book (third video from the top) as nearly everyone sees their fortunes change.

It’s back to what people thought, originally. A push for those on the outlier Saints minus-5/Vikings plus-5 lines, but a victory for all other Saints bettors … and a defeat for all other Vikings bettors.

I feel sad for people who feel compelled to bet on big sports events — as if the big event is not enough to keep them entertained.

There only certainty in gambling, over the long run? The house never loses.

And those who bet already know this, but …

New England favored by 7.5 points over Jacksonville in the AFC title game; Minnesota favored by 3.0 over Philadelphia in the NFC title game.