When I was a little kid watching Return of the Jedi for the first time, I turned to my father when Malakili started weeping over his dead rancor and asked “Why is that guy crying?”
He said “Because it was his pet."
And with the sudden awesome realization that it was possible to have a horrible monster for a pet, and that bit characters have feelings too (see our love for The Venture Bros.), came a few terrible moments of hating Luke Skywalker’s guts.