"Self service" checkouts at grocery stores. I get the idea that the bagging area is also a scale, and that's supposed to keep customers honest. But it leads to so many darn problems, the devices aren't really "self service". And moreover, every time it malfunctions you're reminded by the store that
we don't trust you which seems like a terrible way to treat good customers.
Still, I don't know if it's fair to pick on a technology that's so new. In a way, they're still learning, and they're following the advice that many in the design thinking movement would give: make a prototype, even if it's not perfect, and try it out with real customers.