"Cathars clearly regarded themselves as good Christians, since that is exactly what they called themselves. On the surface, their basic beliefs seem unremarkable. Most people would have difficulty in distinguishing the principle Cathar beliefs from what are now regarded as conventional orthodox Christian beliefs. However, pursuing their fundamental beliefs to their logical conclusion revealed surprising implications (for example that Roman Catholics were mistakenly following a Satanic god rather than the beneficent god worshipped by the Cathars.)"
http://www.cathar.info/1201_beliefs.htm
http://www.cathar.info/120102_implications.htm
http://www.cathar.info/1201_beliefs.htm
http://www.cathar.info/120102_implications.htm