Initially, the plastic inside the connector was white. They started to use black to denote USB2.0 devices, and USB2.0 rapidly became the standard. They at least tried to do something similar with blue plastic with USB3.0.

It's basically the only example I can think of where the plug and socket are rotationally symmetrical without also being reversible. That's the kind of thing where I ask "did you test this before you shipped it?" Thirty years later we're still plagued by the damn thing.