Crispin Glover has a rough history with Back to the Future. While he will live forever in the memory of a certain generation simply for playing the role of George McFly in the original film, his ongoing issues with making the movie is a story that lives in infamy. Turns out he’s still angry about the whole thing. Really Angry.
In an interview with The Guardian, Glover doesn’t hold anything back when talking about problems he had with the movie and writer/producer Bob Gale:
Me asking the questions that I asked [about the film’s ending] infuriated [the film-makers], and they were angry and they wanted to do something that was cruel, which they accomplished. Bob Gale then specifically lied, and said false things about me.
Glover is so angry about the situation that he is apparently writing a book about propaganda in which he will directly address the situation with the movie, saying that it’s "provable that he [Bob Gale] lied" and that the book will prove it. Glover felt the ending to Back to the Future was an implicit statement that money equals happiness. When Marty’s parents are poor, they’re miserable, after the past changes and they become rich, they’re happy. Interestingly, while Glover seems to put the blame on Bob Gale, he says he never brought up his problems with the producer, but rather with director Robert Zemeckis. Regardless, Glover believes that voicing his concerns about this was what led to the fallout that was Back to the Future Part 2.
Glover refused to do the sequel, partly because because of his issues with the first film’s ending. The filmmakers’ solution was to make up another actor with prosthetics to look like the actor. Glover ended up suing over it since it appeared he was in the movie when he wasn’t. He points out, not incorrectly, that they happily recast Elisabeth Shue as Marty McFly’s girlfriend, but didn’t do the same thing for him. He believes the "fake Crispin Glover" thing was punishment for him raising questions and refusing to do the sequel.
Crispin Glover is a weird dude. It’s important that everybody be clear on this fact. He’s sort of like if a character from a David Lynch movie was real. Having said that, his weirdness makes him kind of incredible. His performance as George McFly should really be observed with a critical idea. It’s insane, but in a good way. George McFly is funny, but in a completely different way than the rest of the film is funny. It’s one of those things you don’t notice watching the movie as a kid in the 1980’s but only rewatching it later. We’ll always love him in the movie, even if he’s going to be pissed about it forever.