I've been fortunate so far that I have not had the dreaded writer's block. I have loads of ideas, it's just a case of getting them out of my brain, and onto the screen. Sometimes, if I am going over a scene, I need to think it through and make sure that it works. A single scene could take days to write if it is not thought through. I don't count that as writer's block. But it simply means I must do other things in order to leave the scene, then come back to it, knowing with full confidence that I can make it work.