Most of my requests are along the lines of "This is great, you should write a sequel with XYZ!" Except I already wrote four sequels, including XYZ, several years ago. And they're all posted on the same page, so if they found the original, they would've seen the sequels if they just read the list of titles. Oookay, I'll get right on that. (Sidenote: It's WEIRD getting random feedback to a ten year old story! And ones complaining I got a fact wrong, in fanfiction, when that fact wasn't revealed until a few years after I wrote the fic.)
Glad I'm not the only one who feels that way. From what I've seen on FanFiction.net, quite a few writers get unreasonable requests.
Sometimes I will fill a request, but only if it's something I can comfortably fit into the setting I'm working on.
I sometimes write fanfiction, and a few years back I started a longer multi chapter piece. However, unfortunately writer's block struck, and I began to lose interest in the show the FF was from. I announced to those enquiring that I was very sorry but the piece would not be continued...
...and the next day, I had a message from another user (and not one I knew particularly well either) asking if I would give her the fanfic so she could finish it!
As in, I'd send her the files and she'd continue the story under her own pen name!
Now, although writer's block had stopped my process, I knew how I'd have wanted it to end, so I wrote back and told her that her request wouldn't be possible, but if she wanted to write something based on the general theme and concept then to go ahead.
I know FF isn't like original works, and intellectual property can't be claimed (except in *some* very morally grey cases...), but the nerve of the request staggered me.