I'm bringing our cat to the veterinarian for a checkup. As I prepare myself for a fight with our grumpy cat who doesn't want to go in the little cat travel cases, I get a message on my phone. It's from the veterinarian, saying something like: "Sorry the previous appointments took longer. Yours will be delayed by 30 minutes".

That little message helped me not to be stuck in a waiting room full of scared animals shouting and screaming for nothing. Plus it gave me a bit of additional time to strategise how to get the beast to accept to go in the travel case.

That type of message is something that is totally normal for work colleagues and friends. You just text your friend saying: "Hey, I'm gonna be 5 minutes late". But still, many services don't treat us in the same way friends do and therefore, we end up waiting in a stupid waiting room when we could have used that time in a more interesting way if we had received the friend-like heads-up message from my vet sent me.

This is a first draft of a principle that might end up in a book of the "Service Design Principles" series.