Highly sociable Dagmaraka.
OK, I've found some Polish-German stereotypes (from Gazeta Wyborcza):
Poles joke frequently, even in serious, official situations, while Germans are very stiff.
1944, Cracow. A young Hitlerjugend member comes in a street across a Polish worker. The German wants to shoot at the Pole, but hears a voice: "Don't do it, he's a future Pope, and you will be his successor..."
During a general audience, the Polish secretary of Benedict XVI disappeared somewhere. Then an old German priest recollected some words in Polish and wrote them for the Pope on a piece of paper. The Pope says to the Polish pilgrims: "Defenders of the Polish post office! Come out, you're surrounded!" (First days of the war in Gdansk; and the Pope has phonetic messages which he reads from the balcony)
True story: a Polish woman lives in Berlin. She found an apartment through a real estate agent.When they were signing the contract, the guy says to her: "You know, additionally there is a deposit, 1000 Euro, but you will get it back when you dissolve the contract with me". The Pole said jokingly: "Unless I destroy everything, true?" Then the guy got highly frightened: "What do you mean? You are planning this?"
(Just a joke based on exaggeration)