I don't deny that Polish people are somewhat rude, especially the customer service
I think the so called rudeness of Poles often stems from differencess in priorities. For example the famous "How are you?" - in the UK asking someone how he/she is is a part of the etiquette. Polish people do not ask "How are you?" unless they are friends with someone -
and when they ask a friend, they feel obliged to show the will of listening to how the friend's TRULY feeling. Because what is valued more than political correctness is the genuinity of your concern. If you're not concerned, save your breath. If you ask a stranger in Poland how they are, they'll stare at you - because they assume that you don't really care - why would you? And if you don't care - why do you ask? For Poles there are 2 explanations: either you want to use them, so you pretend to be more friendly than you really are; or you are a nosy person and you just like knowing things that are none of your business.
Actually, it's not like the British people believe that a sales assistant
cares about how they feel - but they seem to value the etiquette more than real emotions or concern - everbody knows that the etiquette is empty, yet they are happy to play that game. My theory is that there's very little of real positive emotions left in the British society, so they hold onto the substitute of kindness, cause without it life here would be just unbearably cold.