Empire brought cinematic science fiction to a new level. Luke isn't just on some operating table, he's suspended in liquid inside a sci-fi tank. Shit yeah! Did I mention I love this movie?
I try not to discuss the scenes that were cut from the movies before their theatrical release. However, the cut scenes are more canonical than anything besides the movies themselves. Often they have very relevant information. Like now, for instance.
After Luke gets out of the tank, there are a few sequences cut out; Luke getting a bandage mask peeled off his face, Luke's emotional revelation to Leia, and Luke and Leia nearly kissing!
Though cut, this scene was included in the theatrical release trailer (the voice over says "It's an epic of romance" just before to emphasize it). You can see it for yourself on the extras disk from the first DVD release of the original trilogy. The near-kiss also made it into the comic book adaptation and a coloring book (see appendix vi). It's okay to feel shocked and amazed. You should. I myself only found this out by visiting these two sites: T'bone's Star Wars Universe and starwarscutscenes.com.
Why was it cut? Because of the later 'revelation' by Luke that Leia is his sister. In that light, any additional material dealing with an attraction between Luke and Leia seems, well ...icky. Luke is starting to think of power, so right now he's trying to get into Leia's pants. Only later, after his confrontation with his father, does this change. Oh, he still wants power, don't worry, he just changes his plan to get it.
When I finally saw the cut kiss, it made Luke's body language during Han and Leia's bickering make sense - he's jealous, pure and simple. He gets super pissed and fumes through the scene until Leia plants a kiss on him. Emotionally, Leia is at least ten years older than either of these two clods, but she seems stuck with them.
She needs Luke close, he's the only weapon the Rebels have against Vader. And she needs Han close if Luke is around - as a Royal she knows the Jedi have spooky mind control powers and Han, as a criminal, is immune to such trickery. She's playing a dicey game of luring both of them with sex.
Be careful, princess. These Jedi can get you to believe anything, even that you're their sister
Star Wars---Empire Strikes Back---Return of the Jedi
Phantom Menace---Attack of the Clones---Revenge of the Sith