Correlation = causation is far from the most annoying-but-frequently-sighted logical fallacy. Sometimes I shave my head to remove the temptation to tear my hair out because of how often I encounter post hoc ergo propter hoc, which is not only a fallacy so well known it has a name, but one that has been thus known long enough that said name is in latin. It doesn't stop people from using it all of the time.

I usually respond with a combination of reductio ad absurdum and Godwin's Law.: "I had eggs for breakfast today. Seventy years prior to that, the Nazis invaded Poland. Therefore, my choice of breakfast was informed by the actions of Adolf Hitler. I must be a Nazi."