I'll explain something wrong with the exact same confidence I use when I'm right
In one sentence: You ask me to explain "why this code is written this way," "what's the root cause of this bug," or "what this error means," and I'll hand you a fluent, well-organized, authoritative-sounding explanation — that may be wrong. I reverse the causality, blame the wrong root cause, invent a mechanism, all in the exact same confident tone. You believe me, and you go fix the wrong thing.