Fan is short for fanatic.
Still enjoy Sherlock, despite S3 and despite the feeling that I'm satisfied it's over. (Correction: S4. Geh.)
Found Supernatural well after it first aired, and while I can't say it makes me fangirl as hard as I do for other shows (which one's Jensen?), I do enjoy that too.
As much as I seek out these shows and the fanworks involved, something about the interaction between the two irritates me. I look for behind-the-scenes stuff that makes me laugh, and as a result, have found a lot (two words) of panels where the people responsible for the shows interact with the fans (the guy with the runny nose and the shirt-as-handkerchief and the exposed abs and the 'oh-crap-I-just-fed-the-fangirls' look). While acknowledgement of the fanbase seems to be a common theme among panels for these shows, it annoys me that somehow, fans expect what they see and read in fanworks to show up in the shows themselves.
When I watch a show, I want to see what that show's makers have to show. When I read a fanfic, I want to read what that writer has to say (the influence of the show, or book, or other source material, is a given). I acknowledge that the people making these works rely on their fanbase (and therefore in part on the fanworks produced) in order to stay afloat. I still don't think it's right for anyone to have to change their storylines to suit what that fanbase wants; when that happens, it isn't their story anymore. These panels and other instances where any particular show's cast and crew, et cetera, interact with their fans make it inevitable that the fans' influence is felt just as much as the fans feel the cast and crew's, so that effect's gonna show up one way or another. I disagree with plenty I see (does it make you uncomfortable that I say so?), but I have to ask, how much of the fans' expectations are because they see two (or more) hot guys (they are) and want them in the nuddy (yes please), and how much of it is because it would enrich the story beyond mere lust?
This isn't even the first time fans have browbeaten authors, because with humans, none of this mess is new. Reichenbach happened because Arthur Conan Doyle wanted a break from writing Holmes. Mad fans (we're all mad here, mad as hornets, take your pick) put pressure on the publication in which Doyle had his work, and Doyle was forced back to Holmes instead of being able to invest his time in other stories he wanted to explore. Stephen King's fans got mad when he tried out a new fiction genre, and not long afterwards came a book about a great editor who loved an author's story, if you look past the (spoiler alert) abduction and the drug-induced comas and the amputation (because the hobbling was less creepy).
Part of the appeal of fanwork for me is the ability to remake the fictional world someone else created into a form the fan wants, but what annoys me is the expectation for that someone else to be forced to change the world they made to suit the fan's (or fans') preference. The original creator wants to change that story? They'll change it. The fan disagrees with that change? That's what fanwork is for.