Disclaimer: I don't own Star Wars.
Standing side by side together on the sandy dunes of Tattooine, R2-D2 and C-3PO watched solemnly as the two suns sank from the sky. The two droids were feeling much like a former master of theirs who they'd met years ago on this very planet - and had just recently passed away.
R2 made a low, unhappy bleep at the memory of his old friend.
"Oh... Don't be sad, R2." C-3PO rested a metallic hand comfortingly onto his little friend's dome-shaped head. "Master Luke lived a triumphant life; he achieved so many of his goals."
The blue astromech let off a puzzled whistle.
"Like what? Well..." 3PO looked away in thought. "He was the one who destroyed the Death Star, he helped Darth Vader to turn against and destroy the Emperor - and he finally became a Jedi. So much did Master Luke accomplish and achieve..."
R2 began to bleep away quickly, as if countering his counterpart's remark.
"What do you mean he didn't achieve all he set out to do?"
A few more whistles escaped R2 - leading 3PO to tilt in surprise, understanding perfectly what his unintelligible friend had just told him.
"Oh...you are right there about Master Luke..." 3PO nodded as he turned back towards the setting suns with his hand still on R2's head. "...He never did pick up those power converters he wanted to purchase from Toshi Station..."
The end.