Story Heroin

This whole writing addiction never works how you expect it to, does it?
It's easy to see how the people in the olden days thought there were such things as Muses and that they were fickle and fanciful.
One minute you get a big craving to write something and the next minute you want to write something else.
I don't even seem to be able to stick to the same genre or even the same medium. Short stories, novels, scripts and articles are pouring out of me like word spew at the moment. The start of them are but then the fickle Muse moves on without finishing the story. That's where the hard work part comes in, you have to force yourself to finish these things and it's hard. It's especially hard when you have a shit job to work around.
I thought a real writer could write anywhere. I heard all those stories about Stephen King writing in the laundry room of a hospital between washing sheets covered in blood and maggots. Yes, maggots apparently, poor old Stevie.
I can't write anywhere though. I can't write at work, it seems to suck the inspiration out of me. It's like a place my Muse refuses to enter.
You have to wonder if this whole writing thing is a gift or a curse. It drives you round the twist if you can't write but society doesn't allow people to just sit and write. If one more person says the word 'productivity' to me I'm going to hit them.
Where did the obsession with being productive come from? Sounds bloody Victorian to me.
Why can't people simply be?