Why are reruns so comforting?

When I come home from work, I turn on the TV and hope that NCIS is showing on USA or Castle is showing on TNT.

Yesterday I was home sick from work and was thrilled to discover a Castle marathon, with a side of NCIS when I didn't like a particular Castle episode.  (There are very few of those, by the way.)

Why are reruns so comforting?

It's not just Castle or NCIS.  I will watch Jeff Dunham on Comedy Central almost every time he is on.  And laugh every time I do.  Or The Incredibles, or The Princess Diaries, or Doctor Who.  I've watched RED, Knight and Day, and Mr. and Mrs. Smith more times than I can count.

There is a comfort in advance knowledge that the show will, or won't, have a happy ending.

There is a release from the responsibility of paying close attention so you won't miss any plot points, and of knowing when your favorite parts will air.

There is pleasure in listening to the favorite conversations of your favorite characters.

It's the same reason I will reread some books over and over.  It's the people in them, their thoughts, hopes, dreams, conversations, and adventures.

I don't know the psychology behind it.  I just know that reruns are welcoming, comforting, and friendly.

I'm grateful to cable television for extending the lives of so many of my favorite programs.

What are your "comfort foods" shows?