Here my mother explains how the priest was trying to convince her to convert. She was subjected to many anti-semitic remarks during her years here including the teachers jokingly adding "sh*t" to her last name and the whole class laughing (Goldberguvna instead of Goldbergova). Finally, one day my mother said to her parents that maybe it's a good idea to convert, and they immediately started making plans to move to Israel.
It is estimated that Jewish population after the war in Poland was around 400,000 (down from about 4 Million before the war). But, during those years, anti-semitism in Poland was so strong, that the number reduced to around 40,000 jews today. As an example, read about the Kielce pogrom in 1946: http://en.wikipedia.org/wiki/Kielce_pogrom, as well as Jan Gross' book "Fear: Anti-Semitism in Poland after Auschwitz".