I know this because I usually mow the lawn at least once during the course of a song's creation.
Writing WHILE mowing is a GREAT way to write songs. Really. Or driving (but it has to be a truck - an F150 works great)...
Seriously.... writing while doing some other "mindless" activity is a great way to "get out of your own way" - and write a very SINGABLE song... (careful in the truck, though).
Noel - I enjoy your PG song blogs!!!