I remember two years ago I came to visit Spain, Madrid from Denmark, so I thought I'm gonna go get myself some summer clothes. I enter the store, can't recall now what it was, but I'm sure some chain like ZARA or similar and I don't see any staff there. As I'm about to go pay I notice these self-checkout machines, never seen them before, apart from grocery stores. Moreover, the machines are smart and I don't need to scan anything, I just drop my purchases on the scales it automatically knows what I'm buying I press checkout and pay. Zero human interaction. Count me impressed.