What are some examples of ancient and medieval "bad philosophy"?

Zizek, Rand, the new atheists, an co. get a ton of well-deserved ridicule because of their philosophical theses are just bad philosophy.

However, I haven't heard of any ancient or medieval (basically any historical piece of philosophy that isn't fairly modern) that is ridiculed. We hear of all the great minds of the time because of their legacy, but who were the Randians of the medieval, Scholastic world? Who were the Dawkins of the ancient world? Do we have any historical knowledge of any people trying to do philosophy and just failing horribly?