In books and movies, why do our favorite characters always have to die?

This question has become the beginning of many very depressing conversations for me and my friend that always end with us laughing at the sweet irony of it all...Each time we have a favorite character, they seem to die by the end of the story. In some cases, the character is the main character and must die at the end to make the story seem complete. At other times, it is merely an intriguing supporting character who ends up dead because they are of no real consequence.

Some examples:

* A Tale of Two Cities: No matter what people say, I love this book. From the moment we see Sydney Carton staring at the ceiling of the courtroom, I loved his whole depressed, drunken, and querulous character. Sadly, it was his fate to be a blood sacrifice to la guillotine.

* Harry Potter: How can you not love a character who rides a flying motorcycle? I nearly put Order of the Phoenix through my bedroom wall when Sirius went through the veil. Unfortunately, I have a sick feeling that my favorite character, Lupin, is next - and all the subtleties are just feeding my already-raging paranoia.

* Star Wars: "Strike me down and I shall become more powerful than you could even imagine." With those words, Obi-Wan flicked off his lightsaber and became one with the Force - all for the sake of saving a whiny little farmboy who may be the savior of the galaxy.

Okay, so they're not the best examples, but it's late and I'm too tired to think of any better ones at the moment...and I'm rambling again. Until later.