Catholic upbringing!! Hence such frequent devastations of Poland by our neighbours.
Lol, I wouldn't blame a Catholic upbringing. It certainly didn't help our neighbours be any less brutal. The Germans were originally Catholic too, and aside from having rather different liturgical traditions, the Russian Orthodox faith is in actual fact very similar to Catholicism.
Being Catholic did make Poles a royal pain in the ass when under foreign domination, though, and probably helped prevent too many Poles assimilating into Protestant Prussia and Orthodox Russia. If Poland had been Orthodox, religious Poles would look up to the Patriarch of Moscow instead of the Bishop of Rome, and since Polish would have been written in the Cyrillic alphabet, Poles would have found it much easier to assimilate into the Russian empire.
Nowadays, the territories of Poland and Germany are quite similar in size, so both countries ultimately ended up mediocre, probably due to, quite simply, their geographical location. Russia was the big winner simply by virtue of the fact that it was the easternmost European power, and the fact that there weren't many people east of the Urals who could check its expansion. Were it not for Soviet domination in the 20th Century, I'd imagine both Poland and Germany would have achieved a comparable level of economic development too.