Characters
Being called an idiot tends to take people out of the dating mood.
— Buffy · Buffy the Vampire Slayer

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker wryly notes that insulting someone, specifically calling them an idiot, is a poor way to keep romance alive. The understatement carries the humour: a plain observation about cause and effect, suggesting affection cools quickly when it is met with contempt.
Context reviewed