I recently had the bizarre experience of going to Manhattan after a wave of “boosters” had been rolled out. I remember standing on a crowded rooftop bar on top of a boutique hotel; attractive couples flirted at tabletops; singles crowded the cocktail area; the sun shone, and everything looked normal. But I kept having the disconcerting sense that I was standing inside a hologram. I could not figure out what was wrong, until I realized — it looked like a crowd, but it did not feel like a crowd. I could see the people, of course, all around me, but...