Common falacies that are believed by just about every Protestant I have ever talked to:
1) Catholics worship Mary.
2) Catholics worship statues.
3) Catholics worship saints.
4) Catholics believe that non-Catholics are doomed to Hell.
5) All Protestants are seen as being "excomunicated" from the Kingdom of God.
6) All priest all pedophiles.
7) The Pope is seen as being illfallable and free of sin.
We worship the Pope.
9) Pope Pius XII was a monster who hated Jews and cooperated with Hitler.
There are many others. Those are just a handful.
Yeah I remember that summer debate with Josh where he kept insisting that southern Catholics pray to saints and you could never tell him he was wrong. What a joke.
My favorite was when some anti-Catholic guy I know made a statement that a majority of priests are pedophiles. You have to look at that statement and laugh (because it's obviously not true) but when I first heard it, I was very angry.