It is the ability to take a joke, not make one, that proves you have a sense of humor.

Eastman’s line shifts “sense of humor” away from performance (being witty) toward temperament (being resilient). The real test is whether you can endure being the butt of a joke without defensiveness, retaliation, or wounded pride. In that sense, humor becomes a social virtue: it signals self-knowledge, proportion, and the ability to keep ego from dominating interactions. The remark also implies that joke-making can be aggressive or self-serving, while joke-taking requires generosity and emotional steadiness. Read broadly, it’s a critique of people who brandish wit as status but cannot tolerate laughter directed at themselves.