First ATM’s (at least in Finland) used to “eat” many forgotten cards. That made customers unhappy and it also cost a lot to the banks. Then the guys designing sw for it revisited their thoughts.
Users only goal in ATM is to get money. What used to happen was, that user put the card in, entered pin code and then told how much money they want. Then money came, they achieved their goal and left. And the card was forgotten.
Currently ATM’s work so, that users are not able to get money, before they take the card out from machine. How simply they fulfilled the need users didn’t know they have. Users would be so much unhappier if they would lose their card. Now they don’t even realise this trick.
Maybe smart homes could grow to be similar in the future. When you are leaving the house, system would check that there no lights on and stove is off. Or maybe there’s much more obvious case I don’t even now realise. Surely something to keep in mind.
I just love these simple tricks to make users being not unhappy.