Being a Sith, Lord Vader lives and meditates on Mustafar, the place where he was defeated and where he believes he accidentally killed his beloved, because the memory is frustrating and upsetting. In fact he has sand specially shipped there, just to piss him off extra hardcore
@LexYeen "And now, my young Apprentice, I have brought you something special to help channel your rage..."
"What is it, my Master?"
"Have some FUCKING SAND!"
@Leucrotta I bet it's specifically from the street he grew up on, too.
@Leucrotta Oh shit, that's what his meditation chamber is: A really fancy sandblasting booth.