I wanted to go to bed early tonight, so I decided to pick a picture and write an American Sentence. Not only was it not quick--I really had to spend time with the words--I was left wanting to write more. I actually had to tell my muse to take a hike. How rude. How absurd!
Recently I had to wait over an hour for my flight, so I wrote a string of American Sentences about stuff I observed just sitting there in the airport. Sometimes when I post ASs on Ning I make up a title that somehow unifies the group of them. They're not necessarily part of the same poem, just hits on a similar theme.
Maybe you really needed to sleep more than anything!