Well, I didn't intend my answer to be a shallow sight-seeing list, as much as a sight seeing list that would facilitate learning and experiencing more deeply. If you go to mass with the Pope, you will learn about the profoundly Roman-Catholic aspect of the Polish people. If you check out the art of Jan Matejko, you'll learn a lot about Poland's history and Poland's cultural mores. If you hang out in the Tatras, you'll learn about Goralu culture. Etc.
In any case, about the Polish people (everything following is, of course, broad generalizations that do not apply to everybody):
The Polish population is pretty close to 100% Roman Catholic, and rather devout. (Jews used to be a major segment of the population, but many were murdered by Nazis in WWII, and almost all of the rest chose to leave after WWII. On a related subject, there is a huge amount of rabid anti-semitism among the Polish people. It's a minority of people, but a significant one; and those with that attitude are quite open and ardent about it.)
They are mostly an extraordinarily kind and generous people, and also very tough people.
Learning English is a major Polish activity (because English is seen as the de-facto language of international business), and so you can communicate pretty well with Poles in English. (Of course, they appreciate if you make an effort to learn Polish.)
They are generally not so fond of Russians and Germans.
They are quite capitalistically-minded.
They consider themselves freedom fighters. They consider themselves to have been the most rebellious against the Soviet regime. They note their significant role in helping the US gain independence from the British. They note their resistance to the Nazis. Etc.
In my experience, they do NOT hold the common European anti-American-foreign-policy opinions, and do NOT feel that their role in Iraq was political expediency. In my experience, they feel allied with the US as true freedom fighters and true capitalists, feel that they have been true friends of the Americans since Kosciusko for these reasons, and feel that they participated in Iraq because of the importance of fighting for freedom. If anything, they have a more untarnished view of the U.S. than I do.
They give a lot more priority to other things besides politics than we might be used to. For example, putting notable scientists and artists on their currency, instead of only politicians.
They do, indeed, love Jazz. They also have an odd predilection for cheesy disco techno-pop. And they like big band music, and classical waltzes.
They are generally pretty reserved, and will wait for you to prove yourself worthwhile before they open up.
They really like good poetry.
--Mike