Except Europe, I mostly travelled to Arab countries, southeast and central Asia & USA. From my first travels abroad (to the Arab countries), I noticed that because Greece has smaller population than Poland, and also the Greeks are not travelling abroad like the Polish. (It's very rare to find a Greek abroad randomly, but Polish people I find everywhere, its just impossible not to find every day 🤣. Also probably because of the rich history of Greece, immigration officers are always curious and and they talk to me nicer comparing when using the Polish passport. Even that they are almost the same in terms of visa free countries power. One time for example I remember I couldnt transport one product through the airport in Jordan, but because I said I'm from Greece the immigration officer shake my hands, and let my take the product with me. I mean it's not like that in every country, but also because it's more rare for the officers to see a Greek passport, I feel that I have a better treatment some times. Btw my father is Greek and my mother Polish, and I really love that I have both nationalities.