Why do a lot of Americans give such a mive **** about socialism?

Speaking for a European point of view all this opposition and aggression to things such as Obama's healthcare reforms that are branded as 'crazy socialism' seems at best misguided and at worst idiotic. After all it does work, you just have to look at Europe and other western countries. Is it just that people ociate it with the USSR, the Nazis and other extreme left governments/counties and ume that's what some degree of socialism will cause? :)