The end

When “Friends” producers Marta Kauffman and David Crane met more than two years ago to pen what was supposed to be the final scene for their wildly popular sitcom, they ran headlong into an impenetrable case of writer’s block.

Try as they might, they sat for days, but the right words and tone just wouldn’t come.

“We kept pitching line after line, and ultimately we just decided not to do it,” Crane said at the time. “We finally looked at each other and said, ‘Well, obviously it can’t be written’ … So we lopped off the final scene. It was just too hard.”

When it comes to putting the finishing touches on a popular television show, producers and writers often find it extremely difficult to do goodbyes – and even more difficult to do them well.

There’s intense creative pressure to not only satisfy the expectations of fans who are emotionally invested in a show, but also the demands of network executives who crave the kind of big-event programming that will deliver substantial ratings.

“I think there’s a temptation to do something clever – something unexpected,” says Tim Brooks, a television historian and co-author of “The Complete Directory to Prime Time Network and Cable TV Shows” (Ballantine, 2003).

“The problem, however, is that by now we’ve all watched so many of these finales that it’s very difficult to do anything that feels truly original. There’s a whole list (of finales) everyone’s got to compete with.”

This month, seven prime-time shows, including NBC’s groundbreaking “The West Wing” and “Will & Grace,” are sailing into the sunset.

Other shows on their way out include “7th Heaven,” which aired its final episode Monday night on the WB; “Malcolm in the Middle” (Fox); “That ‘70s Show” (Fox); “Alias” (ABC); and “Charmed” (The WB).

Unlike “Seinfeld” (1998) and “Friends” (2004), which were riding high in the ratings when they bid adieu, this season’s crop of departing shows are all past their Nielsen prime.

Still, they have their intensely loyal followers, and in their heyday they were valuable pieces of property for their networks. So their production teams all will be hoping to put together a quality swan song and go out on a high note.

This wasn’t always the case. For decades, TV shows didn’t concern themselves with the grand finale. Every episode – even the last ones – would play out like the others. The conventional thinking was that building to some kind of climax would diminish the show’s value in syndication.

“Even shows that cried out for an ending – say, like ‘Gilligan’s Island’ – never ended,” says Robert Thompson, a pop-culture professor at Syracuse University. “When that series went off the air, nothing had changed. Gilligan and the others were still stranded on that blasted island.”

In the summer of 1967, ABC’s serialized action series “The Fugitive” became the first show to demonstrate the seductive power of a finale. At last, Richard Kimble (David Janssen) caught up with the one-armed man who murdered his wife, and proved his innocence. The show-stopper was seen by more people than any single episode of a regular series up to that time.

“It was such a huge success that you would have thought television programmers would have jumped on that bandwagon like crazy,” says Thompson. “But they didn’t.”

It wasn’t until 10 years later and “The Mary Tyler Moore Show,” with its weepy farewell and heart-tugging group hug, that the finale floodgates finally opened.

“At that point it finally clicked in the brains of TV executives: If you’re going to live with these characters for so many years, it’s only natural to want some kind of closure,” Thompson says. “When longtime neighbors decide to move, you throw them a farewell party. You just don’t let them pass into the night.”

And thus the era of the “big-event” finale began. In February 1983, 125 million viewers tuned into the 2 1/2-hour swan song of “M*A*S*H” – the largest audience ever for a single episode.

In the years since, finales for series such as “The Cosby Show,” “Dallas,” “Cheers,” “Seinfeld,” “The X-Files,” “Friends,” “Sex and the City” and “Everybody Loves Raymond” have been treated like major pop-cultural events.

But as the TV finales pile up, it has become clear that the truly beloved ones are few and far between. While the hilarious and totally unexpected dream ending of “Newhart” may be fondly recalled, the surreal finish of “St. Elsewhere” probably turned off as many viewers as it pleased.

When “Sex and the City” was drawing to a close in 2004, fans were divided over the direction they wanted Sarah Jessica Parker’s Carrie to take. Some wanted her to stick with her Russian boyfriend. Some wanted her to wind up in the arms of her old flame, Mr. Big. And others wanted her to snub them both and defiantly sashay off into the sunset on her own. (The writers went for sentiment and chose Big.)

And then there was the polarizing finale of “Seinfeld,” which flatly refused to reach for the Kleenex. Writer Larry David thought he was keeping the show true to itself until the very end when he had Jerry and his insensitive pals jailed for violating a small town’s Good Samaritan law. Some fans and critics ate it up, but many others were left with a bitter aftertaste.

The key to creating a satisfying sendoff, says Brooks, is to avoid self-indulgence and stay true to the spirit of the show.

“You want to tie up some loose ends and make it feel like a natural fit,” he says. “Too many shows try to be overly clever and cutesy in their desire to go out with a bang. Audiences see right through that.”

Thompson agrees. He says the era of the “throw-‘em-a-big-curveball” finale has faded, and that understated farewells such as the one “Everybody Loves Raymond” produced last May will most likely become the norm.

“There was nothing particularly memorable that stands out with that (‘Raymond’) episode, but in many ways it was the perfect ending,” he says. “It was a touching episode that stayed consistent with what the show is all about.”

Of this month’s TV departures, “The West Wing” is easily the most distinctive case. Producers earlier had to deal with the challenge of working co-star John Spencer’s real-life death into the last few episodes, and have already provided the big plot payoff with Matt Santos (Jimmy Smits) capturing the presidential election. The only thing left to do, it would seem, is usher President Bartlet (Martin Sheen) out of office and Santos in.

“It has been an interesting run for ‘The West Wing,’ ” says Thompson. “After four brilliant seasons, it went through a couple of down seasons and now, in Season 7, has really reinvigorated itself to the point where you’d almost like to see it go on a little further with the new president. It deserves to have a good-sized audience turn out for its farewell.”

Of the other finales, he believes “Will & Grace” has the potential to be the most excruciating (“it has already gone into its baroque tailspin”) and “Alias” is the wild card.

“That’s the one I’m most curious to see,” he says. “We already know those producers are prone to break rules. Just look at the history of that show and you know they’re capable of doing just about anything.”

But the next finale that will truly face gigantic expectations from critics and fans alike won’t happen this month, but early next year. That’s when HBO’s superb mob series, “The Sopranos,” is scheduled to bow out.

“That show has been so good for so long that everyone is going to be looking for something that’s nothing short of spectacular,” Thompson says. “If I was a writer on ‘The Sopranos,’ I’d already be sweating bullets.”