Week after week, year after year, you hang out with a funny group of pals, laughing at their jokes, crying at their setbacks and sharing time together — then one day they abandon you.

But don't take it personally: Every television series has to end.

This year, loyal audiences are saying farewell to the characters of "Friends," "Frasier" and "Sex and the City." It's an emotional break for some fans who feel abandoned because they blur the line between "Friends" and friends.

"In TV, you are seeing somebody 22 hours a year, so you have a continuous relationship," said Stuart Fischoff, professor of psychology at California State University. "The mere fact that people have someone that's reliable in their lives, shows up every week and says things that they like [creates a bond]."

Tracee Larson of Dallas, Texas, said Carrie Bradshaw (search), the Sarah Jessica Parker character on "Sex and the City," was like a role model and mentor for her.

"There were so many similarities between the characters and my life as a single 30-something woman, I felt I bonded with Carrie Bradshaw," said Larson, 35.

This bond is particularly strong with television characters who are beamed right into a person's home. But with so many familiar faces signing off the air, some viewers may mourn the loss like an actual friend, said Fischoff.

"We structure ourselves around it. 'I'll be with Frasier on Tuesday.' When they are gone, you have to restructure."

But some fans turn fanatics, he cautioned.

"The average response is they like characters, bring them into their lives, then when the show is over they miss it but then move on," Fischoff said. "When they actually get clinically depressed, can't get it out of their minds and won't stop talking about it, they've gone over to the dark side."

The feeling of loss after a series ends is not new. More than 105 million people watched the finale of "M.A.S.H." in 1983, according to Nielsen, which remains a record number. Some 76 million watched Jerry and company sign off in the final "Seinfeld" in 1998, and 10.6 million tuned in for the last episode of "Sex and the City."

However, audience attachment to television characters seems to be getting stronger as the culture becomes more saturated with media, said Matthew Felling, media director for the Center for Media and Public Affairs (search).

"Our parents were a little sad and nostalgic at the end of 'M.A.S.H.,' but didn't consider it a void in their lives like we have seen after 'Sex and the City,'" said Felling. "Older generations saw TV as a component of their lives. Younger people consider it a fixture. More than ever, characters have become substitutes for our social circles."

Larson admitted that the cosmo-sipping ladies did feel like friends. "I found them as being wonderful characters you don't find very often in TV today. If I could design my own life it would be very close to Carrie's."

Characters on long-running shows can feel particularly close because they are there even when viewers go through a personal crisis.

"Whether you are getting divorced or going through cancer treatments, they are there every week and bring you up when you are down," said Fischoff.

Still, some fans take it to the extreme. Deborah Wilker, a writer for the Hollywood Reporter, said viewers can feel betrayed when their fictitious friends are taken away, and often campaign to bring them back.

"You see it when they announce shows are going to be canceled. The switchboards light up. Save 'Dr. Quinn,' Save 'Ed,'" she said. "There are always people who are going to beg, 'Don't let my people die.'"

But Kate Bilger, of Los Angeles, said she finds ways to spend time with old friends even after they stop appearing on primetime.

"You never get over them; you watch re-runs," she said in an e-mail interview. "All the great shows are still in syndication.... HBO still shows 'Sex' during the week, TBS has 'The Cosby Show' among others, and let's not forget Nick at Night. Pretty much if you want to see your favorite TV 'friend,' you can."

But not everyone is enamored with these extended television social circles. Felling said he finds it depressing that people are so attached to the tube, adding that the networks help create the situation with their slogans.

"Must See TV … TGIF … Oh yeah, thank God it's Friday. You can stay home and watch TV," he said. "Don't go out. Your friends are here inside this box."