As many Catholics have probably experienced, I was recently told by a protestant what Catholics really believe. This, of course, was different from my own understanding.
I had responded to his assertion with my own understanding from the Catechism of the Catholic Church and I forwarded him a link to it at vatican.va.
His response was that my Catechism was not the same one taught in seminaries and he assured me that he had spoken to several Catholic priests who verified this was a true fact.
I ended the discussion at that point as I had absolutely no rebuttal to this type of ignorance.