At first glance, it’s hard to imagine that bonking yourself on the head would make you feel better. I found “Mr. Energetic,” the quaint wooden hammer, in the self-massage section at Tokyu Hands, looking rather low-tech compared to the other dedicated work-the-kinks-out tools. It claims to be useful “whenever and wherever you want” – perhaps while sitting at the immigration office, waiting hours and hours for your number to be called…?