Something I’ve learned writing about the cinema professionally for a number of years is that there are bad movies and bad times at the movies, and the latter are considerably worse. Bad movies can be laugh riots, howlers, like shoddy horror pictures or inane science-fiction, to be indulged in or cackled through or suffered with glee. Bad movies are often likeable, or somehow charming, or else might endear themselves to you with personality or ambition, like, say, Southland Tales or…

My attention was seized, watching La La Land a second time — no longer in thrall to a flamboyance one can hardly help but find seductive — by a rather trifling detail. There’s a moment, easy to overlook amid the whirlwind of whip-pans, showtunes, and dance numbers, in which the anonymous patron of a Hollywood studio-lot coffee shop, technically uncredited but specified on IMDB as “Coffee Shop Customer #2”, approaches Mia (Emma Stone), the barista, and demands to know whether…