Here are some quotes from my Creative Writing class expressing 
what we love about writing – inspiring stuff!
When life gets you down, write your way back up.
Words are your mind; your mind is whatever you wish.
Getting stuck sometimes gives you the best ideas.
An idea for a story is like an unexpected visitor: you don’t want it to leave, but where shall you put it?
The challenge of being an author is making the make-believe seem real.
Poetry is just the end of the road – it’s what you discover on the journey that counts.
Your life is a story – write it!
Poetry is like a light leading you to the full story.
Writing is like something I can’t explain – the rush of pen across paper creating magical new places and characters or portraying your feelings is something you should not miss.
If you can’t eat, sleep or talk, write.
I can never see “Why We Write” without reconfiguring it as “Why We Fight”, any answer to which tends to involve Nazi vampires in submarines – which, unless you’re a very particular writer, may not have the intended inspirational effect.
My own answer is: because I feel happy when I do, and unhappy before many days pass if I don’t.