If the speed and power of the tail wag could be captured, Henry would generate electricity for an entire suburban block. Doggy joy and enthusiasm is obviously an underutilized resource. And then there is the itchy chin scratch. When that leggy piston pumps, it could move a bus! Since Henry is a flea-less beastie, that is a less dependable source of power than the tail wag, but huge never-the-less.
Henry thinks he is cute no matter what he is doing - so he gave me permission to post the scratch video - but only if I cut out the indelicate bottom grooming section at the end of his scratch. Since I live to serve Henry, I cut the portion, but just saying, it was there.