I don't find Japanese history all that interesting. Which is strange because I'm often whining about how I don't know much about it thanks to having an American education, etc. But maybe the fact is that I've just never felt motivated enough to research it on my own?
I dislike Europe in the Middle Ages as well. Black Death blah blah blah corruption of the Church blah blah blah feudalism blah blah blah....though in this case, it's not because it's dull, but because I hear so much about it all the time. Much like the Roman Empire.
On the other hand, ancient China and the Middle East are fascinating. Am currently considering The Fall of Constantinople...
For my reference: http://www.fordham.edu/halsall/source/cde-letters.html