There are quite a few things that encourage me to write a fanfic.
The main reason I love writing my own fanfic is because you are in control of your own pokemon adventure. You can choose any pokemon you want, from Venonat to Garchomp.There's also the fact of the scenario. Most pokemon games are incredibly repetitive. Original trainer adventure, POV of a pokemon or a ranger. in a fanfic you could be in an academy, an evil organisation, a member of the armed forces, just about anything. To me it's like little big planet in pokemon. PLAY WITH EVERYTTHHHIIINNNGGG!!
I get inspiration for a fanfic from the anime series, other fanfic ideas which I mould into my own creation, and/or a movie/drama/program on telly. yes daydreaming does help with fanfic ideas, as you have nothing in the way of distractions.
All in all, i love writing fanfics, drawing manga art, and even writing a bit of poetry now and again. And that is where i have my motivation to write!!!