I hate how the EU has the creation of the Rule of Two and the apparent extinction of the Sith occur at the same time. Yoda knowing about the Rule of Two makes it clear that the Rule of Two existed long before the apparent extinction of the Sith.
I hate how some EU fans twist facts to support the EU. If you show them proof that the EU screwed up, they'll claim that it was actually the movies or the interviewee who screwed up.