It is unlikely you will ever know what a Japanese person is REALLY thinking.
Smiling and being nice and friendly are most important and if they are unhappy with you it is unlikely they will ever tell you.

First you know of it will probably be when when they stop spending time with you.

If it is a Japanese partner it will probably be a very short email telling you they cant see you any more.

If it is a Japanese employer it might be a letter telling you that you are fired.

If it is a Japanese "friend" they will probably just stop inviting you places or making excuses not to accept your invitations.

Most likely you will have absolutely NO IDEA that any of these people were not 100% happy.
Even if you asked them the day before if they were happy with your relationship/work performance/friendship it does not mean that you will not get a short email the next day telling you it is over - with ZERO explanation.

It confuses westerners because we hear Japanese people go on about the importance of having a strong "heart" and being brave.. but when it comes to expressing any sort of discontent or telling someone how they REALLY feel, VERY few of them can do it.
I only know two Japanese who can.
One of them now lives in a western country because, in her words,
"I never know what the f*ck they are thinking!"
(This was a Japanese person talking about Japanese people!!!!)

And don't let anyone's good English fool you.
Maybe they have lived in other countries and speak excellent English and appear to understand western culture really well.. it means nothing.
When it comes to saying what they REALLY think they don't have the heart to do it!!

And, as you can tell by my post, it frustrates the hell out of westerners and hurts EVERY time it happens!!

"What the hell did I do?????????????!!!!!"

Feel better, sweetie?

Yeah, it is frustrating isn't it!!!

If they are not happy it would be nice to know so we can do something about it.. but they never tell us, do they!

"Yes, everything is wonderful!!!!!!!!!"

"Bye bye!!"

If only they realized how rude that seems to us, it would give them a real dilemma!!

Thanks Petina

I should add that I think Japanese people's reluctance to say what they are thinking is a good thing and one of the reasons I live in Japan!

Westerners telling everyone everything they think about everybody and every subject makes western countries a bit to confrontational for me!

The problem comes when Japanese people have learned English but have not really learned how we communicate in English.

When speaking Japanese, the style of communication is different.. so not being direct is not such a problem.

But when Japanese people speak English well but then don't tell us something important that is on their mind.. it is frustrating and feels rude to us.

One moment all smiles and everything is wonderful.. the next moment it is the end of the world!

I agree that tatemae is good for dealing with people on a day to day basis.

But for people who we have relationships with like girlfriends, wives, friends and workmates it makes it very difficult.

I have a few Japanese friends who really talk straight with me (I guess that is why I picked them as friends!!).

It seems to be a combination of how well they understand western culture and what sort of person they are as individuals.
Same as in any country, I guess, some people just can't seem to say what they really think
I am sure it must be frustrating for them because they will be unhappy about situations but not have the courage to say anything!

Yeah, I never feel I have any REAL Japanese friends because of this.
Not saying what they really think creates an emotional barrier.
Same reason I could never have a Japanese wife.

Doesn't stop me having Japanese girlfriends though

If you told someone, probably not a new acquaintance but, a close friend or a romantic partner to be direct with you, do you think it would have any effect? Probably not with a girlfriend because even in the USA I have had problems with not being told what women are thinking. That might not be the same though because I will know that they are discontent, just not why.