As an European, I do think most of people here have a strong preconceived image about Americans, normally being of an ignorant, rude and arrogant person. That may, but just may, lead to some kind of discrimination, but I don't think it's a meaningful one.
What's more, as a person that has been twice to the US, West and East coast, I completely disagree with this view of Americans. It was promoted by a certain left-winged European elite in a specific time of our history, but it stuck.