I choose to view writer's block as a non-existent condition, one fabricated mostly for dramatic purposes in movies where the main character is a writer. Writing is like working out. Those days you just don't feel like doing it or come up with reasons to skip are "writer's block" days. Just like you can have a crappy workout, you can have a crappy writing day. You just work through it, and refuse to believe you're "blocked" and attack that blank page. Also like working out, once you start, it gets easier as you go through the session. You'll always feel great for grinding through it and you'll always feel lousy for skipping.