When you don't understand its ways — and don't care to.
Without being overly dramatic, the widespread introduction of the card chip reader is ruining our lives. OK maybe that was a tiny bit dramatic, but the adoption of the chip reader in lieu of the usual swipe has caused a lot of confusion for shoppers everywhere. Not only that, but the chip reader causes even more chaos when it suddenly (but frequently) decides to stop working, at which point shoppers must use the swipe.
If you've experienced this vicious cycle one too many times — or have been on the receiving end of it as a cashier — you'll relate to these spot-on reactions ahead.