What is it about TV Shows that sucks us in?

What is it about our favorite TV shows that suck us in to their lives and make us identify with completely fictional characters that have no actual day to day interaction in our every day lives?  (I am in no way passing judgement...I have a slight obsession with a couple shows myself.)  I find it hysterical that I myself (in life BEFORE my DVR) would schedule my night's activities around a TV show.  Now, thankfully, DVR has changed that radically.  Oh, and I'm talking about NON-reality TV people...I'm talking about the shows that have characters where writers bring them life, not teenagers stuck in a house and "start getting real".

It's finale week, time for cliffhangers, wrap-ups, and character killings.  Tonight, as I write this, LOST is airing it's series finale.  I personally never got into LOST...but I understand people who have gotten attached to shows.  Lord knows I threw a full on party for the end of my favorite show, Friends. 

I know that there have been shows that have been a part of my life, (Friends having been the biggest one) and that there are shows on now that folks embrace in their own lives.  How is it that we find ourselves completely enraptured in these fictional lives and discuss them at work with co-workers the next day?  However the writers manage it, they do a damn good job at pulling people in!

Back to topic, since it's finale week, I thought I'd touch on a few that instantly come to mind when I think of series that throughout their seasons had touching season and/or series finale episodes.

• Friends - (like you didn't expect me to start with them, come ON) Wait, if Rachel is preggers, then who is Rachel's baby daddy??  Is it Tag or is it Ross?  (Finding out was HYSTERICAL the next season.)  Then there was the series finale.  Saying goodbye to 10 years of Chandler, Joey, Monica, Pheobe, Rachel and Ross...  (Okay, okay, I'm moving on...)
• ER - when Dr. Green finally succumbed to his brain cancer.  I have a distinct memory of my roommate Jen and I sitting on the couch, watching this episode, literally SOBBING and sharing an entire large box of Kleenex between the two of us.  To this day, whenever I hear that gorgeous ukulele version of Somewhere Over The Rainbow/What A Wonderful World, I get goosebumps and flash back to the two of us sitting there crying like babies.
• M*A*S*H - (yes, I know I didn't see this one when it originally aired, but hey, re-runs count) When Radar comes into the OR, and announces that Henry didn't make it home, instead his chopper crashed.  Holy cow.  I heard that the cast didn't even know that was the outcome of the episode until the moment that the actor playing Radar came back into the OR on set.  (THAT is good writing!!!)
• Grey's Anatomy - when they finally at the last minute figure out it's George, and then there's Izzie in her pink dress in the elevator and George in his Army uniform...good LORD pass the box of Kleenex again.

I'm sure that there are others out there that I will think of immediately after hitting the "post" button, but hey, those are the four that come to mind off hand.  Thoughts?