The change which occurred in European society during and after crusade was, The feudal system was eroded. They emerged people who were of middle class, merchants, and tradesmen.
The feudal lords gave some parts of their lands to church which made catholic grew into power and they believed if they help the church by giving out lands they will go to heaven.
Crusades made European curious reason being they started trading exotic goods with the arabs and they made better maps and there was also cultural exchange.
Jews were seen as enemies and so they faced heavy persecution.