The Satmar Rebbe once offered a petitioner an apple. The man declined: “I’m not hungry” (innocently missing the point of the offer). The Rebbe remarked: A Chassid you will surely never be!” Rabbi Aaron Kotler, nearby, quickly interjected: “Say Amen to the Bracha!”
This story was told to me by someone who heard it from Rabbi Yisrael Meir Wallace.
(I don’t know if he said this loudly enough for the Rebbe to hear.)