Re: @ElReg!comments!Pierre - Japanese
About politeness, in linguistics this refers to being polite, as in showing deference (and not only, this is called 'positive face), as well as being impolite or rude, or just critical of someone (this is 'negative face"). Of course, you can be polite or impolite towards your superiors as well as inferiors, and you can do that (intentionally or not) by using an inappropriate level of politeness. Imagine,for instance, someone of superior status being excessively polite towards someone of inferior status. The lower status person will be properly insulted, because he or she will interpret excessive politeness as unwarranted irony.
I think you are correct in saying that Japanese is syntactically regular and therefore easy to memorise, but the difficulty of the language lies in things like the politeness aspect, and other aspects outside syntax as such.
For me personally, another difficulty was learning the kanji, because, unlike in Chinese, most of them have more than one reading, so they each have to be learned together with as many contexts as you can remember.
With regard to counters, there are perhaps hundreds of them, but most of them are obscure linguistic curiosities, and in everyday life you can get away with twenty or so.