Oh, I wasn't referring to thing like "tag scenes" or "missing scenes". Besides I also can understand that fans take their characters and put them into different situations. The wish to explore the characters and the show but still preserving the essential of them - that's something I can understand. It doesn't destroy the show but expands it. I've been writing fanfiction myself and I still enjoy exploring "my" characters and describing feelings that only have been hinted in the show. I love interpretations - including those that differ from my own point of view - because it makes me discover things I might have missed in the show, because it make me see things from a different angle and because I love to learn about the characters - and also what other fans think about them.

Perhaps I didn't express myself clear enough (or it's a question of my bad language skills). My "rant" above was rather about the - as you called it - "One True Shipper", those people who can't talk about an episode or a scene without associating it to their favorite ship. Those people who can't distinguish fandom from canon. Or people who make their fandom canon and don't stick to the bases, show and the characters, AT ALL.

Perhaps I should add that my main fandom is SPN. One fandom (among others) which is quite known for its - well - passionate and particular shippers. I'm afraid I'm getting a little worked up about some fanatics every once in a while.

You might want to read "Textual Poachers" by Jenkins to get a better idea
I'm afraid this might exceed my English skills but I'll google it and try. Thanks for the advice!