It might be cultural as well; I'm Polish and living in UK made me change my habits of answering "How are you?" questions. Same with Dutch from my experience - there are cultures where people say what's on their mind without the "I'm fine, how are you" bullshit.

To be fair though, drama-dumping goes beyond that

How do Poles answer "how are you?" differently to Brits?

Brits will either say "Fine, thanks" or not respond at all. Poles will tell you that yesterday they went to visit their relatives, and now they're tired, or that their cat is sick, or that they having problems with something.

It's a difference between "asking when you don't care about response" vs "asking because you genuinely want to know how the other person is"

In the UK, a perfectly valid answer to "How are you?" is "How are you?"

Yes :D

In Poland you would just say Hej! = I acknowledge you being there but I don't want to chat. But again, back to the point I was trying to make - the intent behind these sort of questions (and answers) can be cultural