The title is a quote from a TV writing teacher I had several years ago. It's accurate on the face of it, but it also points to a larger truth about dialogue in general.
Screenwriters are always looking for quick ways to convey things. And quicker usually equals better. For example, the single sentence, "STEVE JACKSON exits a massive Hummer limousine, flanked by an anxious ENTOURAGE, and walks toward hundreds of screaming FANS," does the same work as a page and a half of expository dialogue about how famous he is. However, this shortcutting principle only extends so far -- and it doesn't give us license to be lazy.
Unfortunately, many writers tend to be the laziest when it comes to writing dialogue. And laziness in that department often leads to the overuse of profanity. It leads to the misguided idea that curse words somehow make characters funnier, or more clever, or more menacing. Which they usually don't. In fact, they often make for some of the least interesting dialogue possible -- whereas the avoidance of profanity can lead to some truly memorable lines.
I've been reading the script for Duplicity lately, after seeing the film and loving it. Its high points are many, but one that is likely to be overlooked is the fact that it has no guns, no real violence, and very little cursing. Yet, it's a hugely entertaining, even thrilling movie that has some of the best dialogue in years. Here's a sampling.
GUSTON: Suspect? That's no suspect... (calling into Bauer) YOU'RE NOT A SUSPECT, ARE YOU, JEFF? YOU'RE A BACKSTABBING LITTLE WEASEL! YOU'RE GONNA BURN, ASSHOLE!
BAUER: (muffled through the glass) I want a lawyer!
GUSTON: FORGET THE LAWYER, WEASEL! WHAT YOU NEED IS A NET, CAUSE I'M THROWING YOUR BACKSTABBING ASS OUT THE WINDOW!
Okay, it's not entirely clean, but it's nothing you couldn't air at 10 PM on network television. And look at all the great uses of non-swears. Isn't "weasel" a million times better than "shithead" or "motherfucker"? Isn't the line about the net a million times better than some generic cold-blooded murder threat? (This isn't even a scene between main characters; the interplay between Clive Owen and Julia Roberts deserves its own essay.)
Putting on the studio hat for a minute, let's also remember that multiple uses of "fuck" pretty much guarantees that a film will be R-rated, and an R-rated film is less marketable than a PG-13. I know it makes writers throw up in our mouths a little to even think about anything like that, but if you want to work within the studio system (i.e., make a living), it has to be a consideration. Duplicity slid by with a PG-13, even though its tone and intelligence clearly make it a film for adults; and I wouldn't be surprised if that gave Tony Gilroy more creative freedom (or even made the difference in getting a greenlight).
Understand, I'm not attacking the use of profanity in general. Obviously, there are plenty of cases where it's genuinely warranted. The constant streams of obscenities in Glengarry Glen Ross and Boyz N the Hood are organic to the worlds those films inhabit -- worlds of endless frustration, exhaustion, even abject misery. Characters curse their way through sentences as a means of both venting and masking their true feelings, and there's no doubt that the films are more effective for it. But very, very few of the movies that trade in that level of profanity really earn it.