Spider-Man 3″ took a huge fall this past weekend. Sure, it took in $60 million, but that was a 60 percent drop-off from its opening weekend, which meant the hype and marketing worked great but the movie itself didn’t go over as well. Why is that?

I think the question lies in that great line from “As Good As It Gets, when Jack Nicholson’s Melvin Udall says to Helen Hunt’s Carol Connelly, “Why the dark?” after a particularly rough night with her son. I want to ask the same question of filmmakers, who tend to move to the dark side when making sequels even though history shows it doesn’t always work.

“Spider-Man 3″ is dark. It has three evil characters, not to mention Spidey and his dark side. Apparently that’s too many bad guys for audiences, and this has happened to blockbuster franchises before.

I first remember the phenomenon when “Indiana Jones & the Temple of Doom” came out, prompting the eventual addition of PG-13 to the rating system. The good guy hero character from the first Indy now found himself in a setting of bugs, animal parts, and child slaves that didn’t go over well. “Indiana Jones & the Last Crusade” saved the franchise and left us all with good feelings.

Another example is “Back to the Future 2.” The good kid and the good doc ended up in a dismal future and an even more menacing present (or was it past?) when they returned to find a world of Biff, gambling, alcohol, drugs, and lots and lots of anger. It didn’t feel good to audiences, who were cool to respond to the third and last film. The ultimate good v. evil franchise was, of course, “Star Wars,” but “The Empire Strikes Back” showed you could make a good movie about the forces of evil that didn’t make people feel dark ‘n icky after watching it. The “Lethal Weapon,” “James Bond,” “Die Hard” and “Star Trek” series also managed this feat, though not doing quite so well at the box office.

Almost every religion has its versions of light and darkness; the Bible is very clear about the presence of good and evil in our world. It’s a spiritual truth that faith-based people don’t want to ignore, but apparently we also don’t want it jumping too far off the screen at us. Spidey 4 may be lighter and brighter, but audiences will probably give it a weekend or two before shelling over the bucks to find out.