Ironically, the person most responsible for angering Star Wars fans is franchise creator George Lucas. An early instance of anger incited by Lucas came when he re-released the original trilogy with new effects in 1997. One of Lucas' most noteworthy changes was in A New Hope, as the debatable scene between Greedo and Han Solo was slightly changed to make it look like Greedo shot first, answering an age-old question about the film. Unfortunately, many fans weren't too happy with Lucas' small alteration to this iconic scene.
Lucas defended this choice numerous times by saying he didn't want Han Solo, one of the film's heroes, to be a cold-blooded killer, which sounds reasonable. Considering that Anakin Skywalker/Darth Vader, one of the main characters throughout the entire series, is depicted as a mass murderer in Revenge of the Sith, holes begin appearing in Lucas' reasoning.