Nothing is as frustrating as arguing with someone who knows what he’s talking about.

The line is a wry observation about how disagreement often feels most aggravating when the other person is well-informed and argues coherently. It hints that frustration in argument is not always caused by the opponent’s ignorance or bad faith, but by the uncomfortable pressure of being challenged by strong reasons and evidence. The humor also exposes a common human weakness: we may prefer debates where we can easily “win,” and resent situations where our own position is forced to sharpen, change, or concede. In that sense, the quote satirizes ego in discourse and the tendency to treat argument as a contest rather than a shared search for truth.