Darth Vader is fighting Obi-Wan (Ben) Kenobi, these are his thoughts.
It wasn't enough. You never gave me enough and look where it's brought you. You're panting, I can hear it, feel your strength ebbing. But still it's not enough. Fool. I can see it in your eyes, even as we're fighting, you think I'm going easy on you out of some lingering attachment. I want you broken before I kill you, pathetic, too weak to stand kneeling before me.
More than that though I want you to lose your calm, I want you angry, hating, fearing, screaming, crying. Your muscles are starting to ache now, we both know I'm stronger than you. You have no idea how good it feels to have you struggling to keep up. The darkside has always been stronger than the light. This has gone on for long enough. I'm ready to kill you now. For once dear Master, I am better than you, I will win. Maybe, if I'm lucky, you'll even lose your unnatural calm, that would be a fine sight for your new protege, would it not? You're less than human, less human than I, such calm is not natural.
I raise my lightsabre with more purpose this time, we both know this will be the killing blow. Then you do it. You calmly vanish into the force, leaving behind only your 'sabre and robes. You deny me even this victory, even though it would have cost you no greater price than the one you have just willingly paid. I call your fallen 'sabre to my gloved hands. I know this 'sabre, I know it well. It's Qui-Gon's lightsabre, still warm in my hand, he believed in me, he would have helped me save Padme. He wanted me. The metal is strangely soothing, I stroke it idly with my thumb. It isn't in the best of conditions but it is interesting, unique, special, and no one else can have it, it is for me, and me alone.
When I get back to my quarters, I put it on my bedside table. The first droid to touch it gets destroyed, the rest of the droids get reprogrammed. The first man to touch it gets the personal touch. I hurt him, make him bleed, he cries and begs, like my old Master never did, like you never did. I let him live, the rest of the men get to see a living example of why it is best not to touch the lightsabre. He commits suicide a week later. I move the lightsabre under my suit. It presses into my side, hurts like all the could-have-beens, a little pain is good for a sith. Keeps them strong. I will be strong enough, some day, have a padawan of my own. I don't have much affection to give them, but I will give them enough. More than Obi-Wan, more than you did, but less than Qui-Gon. Still, it will be all I can give, and the apprentice will be my son, and it will be enough, it will have to be. One moment, was all I wanted, was that too much for someone you claimed to love as a brother? Would it really have been so bad to be human, to care, just for one second?