As a species, with a movie in front of us or otherwise, we like what we already know. We consume what appears and smells safe, predictable and filling. A knish of a movie - for many that’s the ticket, especially in the months of May, June, July and August.

And then, after eating the same lunch for a while, we all hit the wall at some point and realize there’s a fine, even invisible line between “filling” and “fed up.”

For a lot of us this is how it’s been amid the contemporary market glut of superhero movies.

They are not all alike. There’s plenty to debate and wrestle with regarding “The Amazing Spider-Man 2” or “Thor 2” or “Captain America: The Winter Soldier.” But I realized something was up a few weeks ago, a few paragraphs into writing the “Winter Soldier” review. As stockholder-friendly Marvel brand extensions go, it’s a solid and intriguingly plotted sequel, interestingly (if not always effectively) different in style, approach and body count from its predecessor, “Captain America: The First Avenger.” I could, and can, recommend it.

Yet the numbing visual familiarity of so much of it, particularly in its computer-generated effects generica and grinding, prolonged sequences of massive destruction and clobbering hand-to-hand combat, provokes a series of anxious sighs in some members of the audience. I’m not talking about haters or skeptics; I’m talking about the fan base. The believers.

The movies continue to dominate the global box office. They work, to varying degrees; they make money. So why have I heard from so many movie lovers who don’t know how much more they can take?

Critics, too, would likely benefit from taking a superhero film off from time to time. “Something about even a good Marvel movie,” I wrote the other week, “is starting to feel a little bit enough-already.” In his review of “The Winter Soldier” Kenneth Turan of the Los Angeles Times acknowledged a case of “Marvel fatigue.” Writing in Slate, Dana Stevens noted that “it doesn’t make sense to review a superhero movie without mentioning the action sequences, but the sad truth is the Niagara Falls’ worth of movie budgets expended on blockbuster special effects are now wasted on this white-flag-waving viewer.”

There’s something in the air, emanating from the worldwide success of Marvel- and DC Comics-derived franchises. Over at rogerebert.com, editor Matt Zoller Seitz wrote this week of his own superhero fatigue, homing in on the wearying sameness of the effects work across so many product lines. The work, he wrote, appears “designed, choreographed, shot, edited and composited by the same second units and special effects houses, using the same software, under the same conditions. As long as people are talking, there’s a chance the movies will be good. When the action starts, the films become less special.”

Some sort of line was crossed in last year’s Superman reboot, “Man of Steel.” The climactic, apocalyptically scaled (another day, another apocalypse) smack-down between Superman and General Zod was a thing of unholy misery, so protracted and insane in its excess, even fans of the movie began emitting audible whimpers. The latest Spider-Man outing, “The Amazing Spider-Man 2,” suffers from a related malady: a disappointing, cliff-hanging, sequel-setting big finish that follows the movie’s second disappointing big finish, that follows the movie’s first disappointing big finish. It has three climaxes, each suffering from arrhythmia.

The other factor in the superhero fatigue factor is simply a matter of how frequently the reboots are flying off the assembly line. The first Andrew Garfield “Spider-Man” movie came out in 2012, a mere five years after the release of the final Tobey Maguire “Spider-Man” movie. Due in 2016, Zack Snyder’s fanboy dream match of Superman and Batman will likely break various records. But Ben Affleck’s Gotham brooder will land four years after we finished up with director Christopher Nolan’s “Dark Knight” trilogy. We’re dangerously close to “Back to the Future” territory. What’s next - Affleck sharing the same storyline with Christian Bale, brawling over who gets the Batmobile?

Nolan’s middle chapter of the “Dark Knight” saga, featuring an electrifying turn from Heath Ledger, proved that not all franchise showcases are created equal. The reasons many of us are looking forward to next year’s “Ant-Man”? There are many, but here are two. No. 1: It could be the start of something big; it’s not a retread, at least not on paper. No. 2: The director is Edgar Wright, whose wit, hyperkinetic panache and facility for staging action made everything from “Hot Fuzz” to the recent “The World’s End” well worth seeing.

It can be done; these movies can do more than make money. Sometimes they can feel like movies, rather than another successful opening of a new Olive Garden.