Instead of the usual button-down dress shirt, Musk wore a single-breasted charcoal peacoat, which he opened wide at one point to show off the words “tech support” in large letters on a black T-shirt.

I was happy to leave all that in the past, until I saw Timothée Chalamet’s new look and remembered how ridiculously fun it was to dress with complete and utter shamelessness. For the last few months, ...