In 1980, the Beacon Theater in Manhattan held "The Worst Film Festival," a Cannes of worms that showcased such lambasted turkeys as "Plan 9 From Outer Space," "They Saved Hitler's Brain" and the all-midget musical western "The Terror of Tiny Town." Attendance was robust, but then organizers must have known: no one would watch a marathon of truly bad films, because truly bad films are unwatchable.
Movies like Ed Wood's "Plan 9" are so transcendentally inept, they're fun to gape at. It's the films that aspire to greatness — social forklifts, awkwardly "elevating" the human spirit — that give bad a bad name.

Filmgoers can frequently tell, from the jackknifing trailers alone, when a movie like last year's "Pay It Forward" is going to stink like roadkill on the grille of a Greyhound.

Acclaimed as a "mesmerizing" "masterpiece" "that makes us ponder the very nature of love," [Steven Spielberg’s] summer film "A.I. Artificial Intelligence" raises the question: is it the worst movie ever made? A tale of a perfect child robot programmed to adore his human Mommy, this collaboration between Mr. Spielberg communing with the dead Stanley Kubrick has, with its waxy sentiment, Simonized filmgoers and polarized film critics.

Bipolarized some of them. "An extraordinarily accomplished movie," wrote The New Yorker's reviewer, "but a failure." The filmmaker Lloyd Kaufman was less sanguine. "Emotional pornography," he called "A.I." in a recent conversation. A "soulless prefab blockbuster that wasn't so much written or directed as assembled by a committee intent on creating a product impervious to criticism of any type." 
For Mr. Kaufman, "A.I." is an embarrassment of riches. Among its richest embarrassments are John Williams's soaring, boring scoring; a Robin Williams cartoon voiceover; at least four would-be endings, which force filmgoers to get halfway out of their seats and sit back down again, as if playing chicken with Mr. Spielberg; the omnipresence, in a pivotal role, of Snuggles the Fabric-Softener Bear; and young Haley Joel Osment ever looking heavenward, presumably toward Mr. Spielberg, once again serving as a preachy, faux- mystical deity. . . 

One high-placed Warner Bros executive, who wishes to remain anonymous for obvious reasons, offers her list of Avoidance Rules — a sort of moviegoers' equivalent of the warnings issued by flight attendants before takeoff.

Locate the exit nearest you, she says, before screening any film directed by big-name male actors or Brian De Palma, any film that features Robin Williams in a beard, any film scored by John Williams, any film starring Juliette Binoche or Kevin Costner, any film that features Robin Williams clean-shaven, any film directed by a woman and proud of it, any film that features Robin Williams in a yarmulke and any film positively reviewed by anyone associated with National Public Radio.

-- Franz Lidz and Steve Rushin, "How to Tell a Bad Movie From a Truly Bad Movie," New York Times