You know I wrote you a PM regarding this, because you wrote me one asking for answers due to my roleplaying. I'm going to provide more answers here, specifally about each area of fandom that I have been involved in. Why am I doing this when you already have answers from me? Because I have way to much spare time and no life. So here goes.
I'm going to start with fanfiction because in my opinion, it's the one I'm probably worst at. I read fanfiction because of the Twilight fandom. I hate admitting that a lot of my fandom experience is from Twilight, but it is and I have to accept that. I read Twilight fanfic on a really good site that actually has some really good Twilight stories. I liked the AU ones most, with no vamps and such. But I never wrote a Twilight fanfic because...no inspiration. I began reading Harry Potter fanfic later and I got so many ideas. Just being a part of a fandom and observing gives you ideas. Everybody has the capability to have ideas and be inspired and fandom will bring that to the front of your mind.
And so, I began writing some peices that were left unfinished. So far I have never written a fully completed story. One day I hope to complete some Buffy ones though. It really helps your creativity just to see what others can do and learn off them, and that's not going to happen anywhere else but in fandom.
Art is another one I'm going to comment on, although I got into it recently. I only just downloaded GIMP and have taught myself how to use it. I haven't done alot of experiemnts yet but I think I'm learning and I hope I'm alright at it. Looking at everyone elses art really makes you wonder things like 'how did they do that effect' or whatever. So, you're inspired...once again. And now I love making banners and desktops and icons. I always get ideas, there's never a shortage and although they're not fantastic, it's a lot of fun.
FAN VIDDING, this is my favourite creative medium aside from roleplaying which I will mention last. It's just so exciting when you have ideas for songs to put together with clips and you get inspired. It was actually Katie's (xfivebyfive) videos that inspired me to begin making my own. Yeah, sure...I make them on Windows Movie Maker but to me, they don't have to be that complicated and I still love my videos. You can do a surprising amount of things on WMM, it's good.
I just realized that there is another way I let my fandom show! When I get into something fandom-y, me and my friends get WAY obsessed and guess what we spend all our time doing? RE-MAKING IT. We act, we're actresses and fandom has given us a way to express that. I love re-making scenes and uploading them to YouTube. And it's just for fun, we have a load of fun doing it. It's actually probably my favourite thing I do that's part of fandom. It's a rare form of expression but it's so much fun. Getting to step into the shoes of a character and have someone tell you that you did a good job. There's nothing better. We're going to re-make OMWF and The Body sometime this year if we have enough time. EEK
And lastly, roleplaying...well, I would comment but you have my comments regarding this.
So, in my opinion. It really inspires you, that's what fandom does. You get ideas from it, you join forums because you're so excited and wanna talk about it with people. It also is a way to have fun. It's just something that you can do at the end of the day that you are doing for you...not anyone else. So it's letting you be creative while having fun AND learning. Why should people discourage that?