One of Jefferson's misguided ideas regarding European affairs is that American neutrality would be respected. Jefferson believed that if the United States remained neutral, such a position would be respected by France and England. The misguided element here is that American neutrality could be maintained. The result was the American forces were impressed by both French and English forces.
Another misguided element was Jefferson's perception regarding American response. Jefferson believed that the passage of the Embargo Act would curtail European interventions against American forces. This proved to be misguided. The Embargo Act did nothing to stop the harassment that was being experienced at the hands of the Europeans. Additionally, it created much in way of economic hardship on a domestic front. This helped to construct a reality in which Americans felt intimidated in Europe and could not find any sanctuary from it even on a domestic level. This represents another misguided proposition regarding European affairs.