I can only imagine Poland is fairly similar.
It depends on which European countries you were in. The culture, mindset and people vary quite a lot from country to country. Also, it's been said many times on this forum but holidays are a very different matter to living somewhere especially when you have to navigate bureaucracy and find how differently things are done from what you're accustomed to.
One of the things I find difficult about Polish people is that they are somewhat reserved but if they decide they want to be friends with you, they tend to smother you a bit. For me as an Irish person (so also European) I am accustomed to the casual friendliness and outgoing manner of my counytrymen which makes it easy to interact on a day to day basis, but I find the 'be my best friend forever' vibe of Polish people a bit overwhelming. They're very nice, but it's just too much.
Also they don't read signals, you have to be very direct and blunt with them or they don't get the message. I'm not comfortable with that, as such interactions can seem rude/confrontational to me. It's a different communication style.
Another thing is that people in an 'official' position get very defensive and quite angry if you ask for information and they don't have it or if you press them for details. My husband, who is Polish, and myself were once doing some business with a Notary's office and I asked the secretary a few polite questions about the process in the same way I would in Ireland and she replied to my husband 'will you tell your wife that if she keeps asking questions Iike this I will have to ask you to leave' !!!
Recently we had to go to a government office on some business and when my husband asked a question about something not very complex or controversial Pani Kommandant snapped 'What are you asking me for? I'm not a lawyer'. Another time, he was talking to a goverment department and they told him he had to call another internal office. When he asked for the number, the girl actually laughed and said 'look it up'. My husband calls it boorishness and it's found at every level in Polish society. On that occasion my husband 'lifted her out of it' as we'd say in Ireland :)) In other words, he told her in no uncertain terms what he thought of her. That's one of the weird things about Poland, how easy it is to end up having a row with a complete stranger when you're not an aggressive person at all by nature.
They probably seem like trivial things to you but when you have to deal with that every day it can get very wearing.