Probably you're aware of the importance of bowing in Japan. But if you haven't lived in Japan, you may not have considered the ubiquity of this gesture of politeness--how useful it is, and how expected, on so many occasions. It so becomes second nature here that people (including non-Japanese) find themselves bowing even when they're on the phone.
So if you think about it, it might not seem so strange that an American, one who spends most of the year in Japan, might accidentally bow to people in various places in the U.S. Just as we have to train our brains for driving on the right side, not the left, while visiting the States, we must remind ourselves not to bow to shopkeepers, neighbors, and others with whom we have contact. Not that bowing is a bad thing, of course, it's just not exactly the expected thing. Nor is openly gaping at all the fat people in skimpy swimsuits at water parks, but that's a whole other story.
So anyway, when we come back to Japan after summers away, we have to train ourselves all over again, and sometimes we start a bit early. The week before we left Texas, Husband and I were out running a few errands, pimpin' it in my grandmother's huge '90s Lincoln Town Car, bane of First Child's '08 summertime existence (oh, the tragedy of embarrassment!). We pulled out of the bank parking lot and immediately met up with a monster truck containing two rednecks (don't ask how we knew they were rednecks; we're just adept at spotting them after many years' practice).
Instead of waving, or doing the increasingly-popular American gesture of nothing when making a traffic "oops," Husband bowed. Not a deep bow, but still. Those guys probably got a charge out of it, if they even noticed. Or more likely, they were simply bemused. Either way, Husband and I went on our way, chuckling about it and realizing we were probably ready, mentally, to go "home."