I HATE it when my friends use (butcher really) the Japanese language
I know exactly how you feel. Although I'm not Japanese, but French. Its incredibly anoying when people try to speak some french to seem smart or elegant, but just end up sounding like idiots. God, the number of times that people, after realizing that I have a french name go "Parlez vous francais?", but say it with such a terrible english accent that it makes me want to strangle puppies. Or all those french expressions people seem to enoy using, like "deja vu" which means "already seen", but everyone says it as if it was "deja vous" which makes absolutely no sense since it means "already you". It also pisses me off in all the movies when they have a supposedly french character that speaks alot of french, but to an actual french speaker it sounds so horrible we'd rather hear nails scratching a chalkboard.

Oh, and all the people (usually art students) that wear berets also annoy me. You're not French, so stop wearing berets! In fact even in France virtually no-one wears them. Why? Because we realized that they look stupid so we stopped. I mean, if your gona copy something from another culture, at least copy something good, like our cooking. It'd be as If someone wanted to copy Americans but rather than take freedom of speech they copy the high crime rate.