“Sa-a-a-d movies always make me cry,” sang Sue Thompson back in 1961. Okay, but what do bad movies do? They make us cringe, nod off, guffaw (when we’re not supposed to), and sometimes just walk out of the theater.

Some bad movies, of course, attain a kind of iconic, ironic “so bad, it’s good” status. People will watch such critical bombs as “Showgirls,” “Anaconda,” “Sharknado,” and the celebrated “Plan 9 from Outer Space” just to laugh at them, or to bask in their mediocrity.

Most truly awful examples of the cinematic arts aren’t worth even that kind of attention, though. They’re just stinkers.

Click here to see the 100 worst movies of all time.

What makes movies bad? Weak story lines, incompetent direction, poor technical quality, and of course amateurish performances can all be factors. But many bad movies boast first-rate actors. In the list below, you’ll find revered old-school thespians like Michael Caine, Sean Connery, and Richard Burton, as well as such younger stars as Emma Stone, Renée Zellweger, and Ben Affleck. And big-name directors can be involved, too. For instance, M. Night Shyamalan, John Boorman, and Sidney Furie are all represented here.

What critics seem to single out time and again in lambasting bad movies is their lack of originality — their derivative story lines, clichéd dialogue, and rote performances. It’s probably no accident that many of the bad movies listed here are inferior sequels to critically acclaimed and/or commercially successful predecessors — cynical or at least creatively bankrupt attempts to cash in on somebody else’s success. Somehow, these seem even worse than low-rent, non-sequel attempts that are merely inept.

To determine the worst movies of all time, 24/7 Wall St. created an index based on each film’s Rotten Tomatoes average critic rating, Rotten Tomatoes average audience rating, and Internet Movie Database average user rating. To be considered, each film needed to have at least 5,000 Rotten Tomatoes user ratings, 10 approved Tomatometer critic reviews, and 10,000 IMDb user ratings.

We averaged the user ratings from Rotten Tomatoes and IMDb and weighted by the number of votes for each. The combined user rating was then averaged with the Rotten Tomatoes critic rating.