The screenplay for ROTJ is a mess in parts, but it actually is quite clever at making the audience believe in stuff that GL came up with on the spur of the moment.

I’m talking, of course, about the idea that Darth Vader was the same person as Anakin Skywalker, which wasn’t suggested even by ESB (where Vader claims merely to be Luke’s father, not to be the same guy as Obi-Wan’s best friend).

Meanwhile, ROTJ somehow manages to make bits of storyline that had been planned since the first film – i.e, the whole Luke/Leia brother-sister incest plotline – look completely artless and spur-of the moment. It’s like a goddam magic act, I tells ya.