Regarding the bow President Obama made to the emperor of Japan. A friend of mine has a common sense take on the bow with one commentor strenuously disagreeing. Having lived overseas I believe it is important and well received to show respect for a host's culture and traditions. I do agree with my buddy that President Obama was most likely not given adequate or correct briefing on proper protocol.
Now, as to why Americans (mostly those on my side of the political divide) are upset over this is because the bow is viewed as submission to an unelected hereditary ruler. Many believe President Obama is confusing diplomacy with obsequiousness. Of course, petty partisan payback has something to do with it too.