Yoda’s lesson in Empire. The way the music swells when he says “You must feel the Force around you” is peak Star Wars for me. A close second is Han and Leia’s “scoundrel” kiss. More romance in 3 seconds than in the entirety of Attack of the Clones.
I firmly believe that this scene is the soul of Star Wars. Fitting that it sits now directly in the middle of the middle film of the middle trilogy.