I read an essay by Chuck Klosterman (in a book called "Sex, Drugs and Cocoa Puffs") about how the end of "Empire" was exactly why members of generation X turned out the way they did.

I think it’s the best ending in the series. That’s an opinion that has evolved over the last few years. When I first saw the movie (the first Star Wars movie that I saw), I thought it was the worst ending of all time. Looking back, though, it’s clearly the best, because it is really the only way to end the movie that came before it.

Not only does Han deliver the best love scene of all time when he’s frozen in the carbonite, but every other memorable scene in the series is in this movie. Luke gets beaten down enough to realize he isn’t the best there ever was, and Darth Vader tells Luke he's his father - in one fight scene. Vader walks away having already shown some ability to turn his back on the Emperor by offering to rule with Luke at his side. We learn from Yoda (not really at the end of the movie, but in the middle when Luke leaves Dagobah) that there is another who could bring balance to the force. And it's got Billy Dee Williams.

To tack on a happy ending to that would be like eating a full steak dinner and then being asked to eat a second steak before you leave the restaurant. The audience needed time to digest the awesomeness.