Punch and nibbles, like “Sherlock”

During Thanksgiving week, from the soft neutral cocoon of my parents’ guest room, I burrowed into an impulsive rewatch of the BBC “Sherlock” — yes, the Benedict Cumberbatch era, all sculptural cheekbones and good outerwear. I’ve seen it enough times to carry around a private hierarchy of favorite episodes (my shame-free Roman Empire), including the first season’s “The Blind Banker.” It has everything: cyphers, priceless antiquities, a rogue circus troupe. But the moment I always wait for is a micro-scene — practically the size of a breath — that glows like a coal in the larger mystery.

In it, amid all the breathless detectiving, John Watson (Martin Freeman, forever the patron saint of beleaguered charm) has managed to land a date with Sarah (Zoe Telford) from the surgery. Bless him. Excep