I don't really know if I believe in writer's block. I believe in getting stuck in a story because I don't understand something or haven't given it enough thought... But that's never lasted more than a day or two for me.
My bigger problem is to do with perfectionism and letting it shut down my ability to write with any speed. So far, public accountability and deadlines have been able to overtake perfectionist inclinations.
But I might have to revisit these ideas if the day comes that those motivators stop working for me.