Mental illness isn't quite right. It's just that Polish sense of having been screwed over and cheated by history despite being very, very special -- a feeling of grievance and entitlement felt by others than the Poles. And to be fair about it, the Poles had a pretty tough 250 years at the hands of their Russian and German neighbors. On the other hand, when Poland was independent -- both before the Partitions and between 1920-39, it didn't demonstrate a particularly high standard of good sense and good judgment.