Complaining about Japan to Japanese people is a waste of time and will affect your relationships.
I’ve been guilty of this, we all have.
It’s hard not to complain about some elements of Japan that just don’t make any sense to Westerners, but complaining to Japanese friends about this will not help, will change nothing about the situation and will just cause problems in your relationships with them.
Let me explain why with this analogy:
Imagine that your family hosts a foreign exchange student for a few months. They are doing a semester abroad studying English at a university near your house.
Then imagine that you talk to them one day and they start telling you about the annoying things your parents do. They say that your dad belches all the time and can’t cook, and your mum is always cleaning everything and it makes him uncomfortable that everything has to be clean all the time.
“God they are just so annoying, right?”
You are probably gonna start to think that this exchange student is a bit of an ass for insulting your family. He has only been there a few months and he does a whole bunch of things that are irritating to you too, like watching loud TV shows late at night when everyone else is trying to sleep, or not recycling anything.
Even if what he is saying is true, your instinctual reaction is going to be defensive. This is how Japanese people see your comments about bad things in Japan. Japan is their parent, and you are insulting their parent. You would probably feel the same in your own country.
This is why saying negative things about Japan and Japanese people isn’t productive, and can hurt your relationships. Think about it from their perspective and it is easy to see why you should keep it to yourself or talk about it with other foreigners if you absolutely have to. As a foreigner you will do things that Japanese people find irritating too.
Figure out how you can process the difficult things in Japan better yourself, and re-frame your perspective. Realise that you are the different one in Japan, and that you may need to adapt and be flexible in order to enjoy your experience more.