People often ask critics what the best movie they’ve seen this year is, which makes for interesting conversations, and then follow up with what the worst movie is.

That’s usually tougher to answer. So consider this a thank-you to the makers of “Left Behind” for giving me a solid answer.

“Left Behind” is a terrible movie, bad in almost every way, not even qualifying as so-bad-it’s-good material. The film, directed by Vic Armstrong, is based on the series of novels by Tim LaHaye and Jerry B. Jenkins, about the Christian Rapture, in which some people disappear, taken by Jesus, while others remain on Earth.

Or, as the production material says, “The most important event in the history of mankind is happening right now.”

Sounds big. So you’re making a faith-based movie and you want a big name in your cast. Bigger than Kirk Cameron, who starred in an earlier version. So whom do you approach?

Hey, let’s get Nicolas Cage to do it. Sure, he was pretty twisted in movies like “Wild at Heart” and “Leaving Las Vegas.” But if he’s willing to be in those “Ghost Rider” movies, he’ll be in anything, right?

Cage plays — with as little energy as possible — Rayford Steele, a pilot married to Irene (Lea Thompson), but since she’s gotten religion, as they say, in the last year or so, his eye has begun to wander. This makes for an awkward surprise reunion at an airport with his daughter, Chloe (Cassi Thompson), as he’s flirting with a flight attendant (Nicky Whelan). While Chloe is there she runs into Buck Williams (Chad Michael Murray), a rugged, famous television journalist.

As fate would have it — you can say that about pretty much everything that happens in this movie — Buck is on Steele’s flight. Meanwhile Chloe goes home and argues with her mother; she’s not any more comfortable with her mom’s religious interests than her father is.

Chloe heads for the mall with her little brother, and while they are shopping, poof! He’s gone, just like that. So are some other people, at the mall and in other places, including the co-pilot on Steele’s plane. It seems random, but Chloe and her father gradually begin to understand what is going on, thanks to Irene’s proselytizing.

Up to this point the film is a study of a family and its problems, and where faith fits in. It’s heavy-handed as all get out, but it’s trying. But once the Rapture actually begins, the film takes a major shift, and the focus becomes getting Steele’s flight home safely. It’s like it turns into “Airport 1975,” and Cage is Charlton Heston.

Mini-dramas play out inside the plane, involving, among others, Shasta Carvell (Jordin Sparks), the wife of a professional football player, and her daughter; the flight attendant Steele has his eye on; and Melvin Weir (Martin Klebba), evidently the angriest little person in the world.

Also, the co-pilot disappears, and the plane is running out of fuel, and one of the engines is damaged, and some of the equipment is malfunctioning and … You get the picture. All that’s missing is Lloyd Bridges in the control tower saying, “Looks like I picked the wrong week to quit sniffing glue.”

OK, bad movies happen. A lot. But what’s particularly unfortunate here is that faith-based movies arrive with a built-in audience, one that is eager to like what they see, because it is a pop-culture reinforcement of their beliefs — beliefs that are often disparaged in that world.

And that’s what is ultimately so disappointing about “Left Behind”: That audience deserves better.

But that’s not the worst of it. What really sticks with you are the lines that end the film, when one character says, “This is the end,” and another, no doubt with one eye on heaven and another on a series of sequels, says, “No, it’s just the beginning.”

Now that’s scary