People
Among those whom I like, I can find no common denominator, but among those whom I love, I can: all of them make me laugh.
— W.H. Auden

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker can find no shared trait among the people they like, but notices one among everyone they love: they make the speaker laugh. The contrast gives humour a special place in this personal account of affection. A broad comparison resolves into one simple, intimate measure.
Context reviewed