It's because since getting back into writing about a year ago I've really fell in love with it. I also tend to write on my lunch breaks at work and because I work in the games industry most of my free time at home is spent doing a bit of writing too rather than playing games all the time. I actually had a look at all of the pieces I've written since starting up again and was surprised at the number of things I have done. A few of them are one-shots and I have the side stuff on my AO3 as well but it was weird.
My next NGE based one is only going to be short too, I've started writing it but I'm going to go through it and do some editing before uploading the first chapter.