I keep meaning to write in depth about Krypto-revisionism. It's the concept that we all reject certain aspects of a storyline, concept, plot, or idea in ongoing fiction series.
I wish the wonderful column Mark Evanier wrote on the subject was still online. It is the first entry in his wonderful essay collection Comic Books and Other Necessities of Life.
The best part is the idea that it happens kind of naturally. If I try to think what James Bond movies fit in the continuity in my head, I start coming to big walls. Thunderball and Never Say Never Again are sort of the same story and both sort of fit as a single event and sort of as two stories. Jaws exists, but neither of the movies he appears in are part of it. It's really a mess that makes more sense just living with it then it does trying to make sense of it.
The trouble with too many geeks is they love to codify things. They love to define which things happened and which things didn't in some kind of defined "canon". I understand the principle of this impulse, but somehow it seems less fun than reading comic books, watching TV and movie series really ought to be in most cases.