Bruno's father laughed, which deeply offended him. Bruno despised it when adults ridiculed his lack of knowledge, especially when he was genuinely curious and asking questions to learn. This reaction made Bruno feel more upset and annoyed, as he wanted to understand things but was dismissed instead.

Bruno's feelings highlight his innocence and desire for understanding, contrasted with his frustration when others treat his questions as silly or laughable. The scene emphasizes the tension between Bruno's curiosity and the dismissive attitude of adults around him, underscoring his young perspective and the emotional impact of such dismissive reactions.