Law / EU citizen - exceeded 3 months in Poland [6]

I made the same mistake - only after a year did I get my register. Got a pathetic piece of paper that anyone could have printed to be honest.

They didn't make any problems for me. Might depend on whether you have a job though - they are worried you will leech of the Polish benefits system as unbelievable as it may sound.

this is pretty comprehensive:
mazowieckie.pl/en/for-foreigners-1/european-union/registration-of-an-eu/388,What-documents-do-I-have-to-submit.html

UK, Ireland / City management - differences between Poland and UK [20]

Dealing with snow springs to mind - Polish cities do so well, British cities act as if snow is a once in a million year occurrence and are never prepared. Think public transport is generally better too (certainly in terms of value for money - comparing Warsaw to London so not 100% fair as latter is so much bigger)