[confuzatron]

USB plugs/sockets are awful. Sure, you can't insert them the wrong way round, but visually it's hard to see which way round is the right way without trial and error. The position of the USB symbol is supposed to help, and does to some extent.

USB plugs should either work successfully inserted both ways round (like this battery system), or be asymmetrical (and even with asymmetrical plugs, things can get annoying when you cant get a clear look at a socket - eg SCART + the backs of AV equipment)