A couple come to mind for me:
1) That we consider Catholics to be the enemy.
Most evangelicals I know don’t think about Catholicism or mention it at all, and when they do, they know Catholicism teaches different things but most consider Catholics to be fellow brothers and sisters in Christ. In fact, I consider Catholicism to be somewhat of a big brother/mentor from whom I can enhance my faith in Christ.
*Note: The only exception I can think of are the radical fundamentalists, who consider everyone not like them to be in error and in risk of eternal damnation. *
Most evangelical Christians I know are just every day folks who are doing their best to love and serve Jesus and seek God’s help in their daily lives and struggles with their families, work, and other aspects of their lives. Catholicism rarely, if ever, even crosses their minds. Many would consider Catholicism to be just another Christian denomination to choose from – not a big arch-enemy or anything like that.
**2) That we somehow disrespect or hate the Virgin Mary. **
While Protestants don’t pray to Mary, no evangelical that I know speaks badly of her. They just tend to focus on her Son and not her. I realize that Catholics might consider the lack of attention to be a form of abandonment or neglect, but I think most protestants want to steer clear of anything that might be construed as being worship or adoration of her.