I've been tossing an idea about accomplishment around my head for a few weeks now: if you want to get something done, get other people involved. That's not to say that everything you do must be a collaboration, but that there's some third party -- other than you and the work itself -- to see if you fail to make an attempt. There has to be someone to disappoint. Sometimes, as you've just found out, the mere presence of another -- and the attendant expectation -- can be enough to stoke the fire.