Usually it would be some common mistake/misconception, eg. applying special relativity in a non-intertial reference frame, but occasionally it might give a real insight into the analogies and methods used to teach a concept.
Say that you encounter a conspiracy theorist. When you point out that his theory is crazy, you don't want him to propose to agree to disagree, right? At that point, I feel like I might be wrong, because I'm the most argumentative. Get what I mean?
"Anyone can make a cryptosystem that he himself cannot break."
Just take up fishing or something. Or if you really want to get into physics, enrol in a PhD program, or even some online courses.
Physics is weird and unintuitive, but that's just because we're living in a simulation which was sloppily coded by the lizard people.
If you read that the person involved doesn't seem to be enjoying the experience; they frequently attack others; they take up quite a lot of time; etc.
Most of these people were old, many engineers (edit: which the article agrees with) with a former basic knowledge of physics. They kinda reminds me of the old professor in the movie "Proof", that has lost grip on reality and invented his own "proofs". Or the movie "A beautiful mind" when he's on his worst. It's a bit sad, really.