Earlier this summer news broke confusing one Presbyterian denomination for another. In this case it involved confusing the larger and more theologically liberal Presbyterian Church USA (PC-USA) for the smaller and more conservative Presbyterian Church in America (PCA). I am a minister in the latter denomination. This confusion quickly led to a retraction and correction about the breaking news. Shortly thereafter one writer took some time to formally list the differences between the two denominations. That article can be found here.
Presbyterian denominations aren't the only ones who get confused with each another: It happens all the time among Lutherans. Here is a witty video that highlights the tension members of conservative churches feel when they discuss church matters with people unfamiliar with the teachings of Scripture.