Characters
You're so gullible, McFly!
— Biff • Back to the Future
Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker mocks McFly as easily fooled, using the surname like a jeer. The line is a taunt that turns someone's trust into a weakness, with the exclamation suggesting a smug, gloating tone. It combines teasing contempt with a claim of superiority.
Context reviewed