As human beings we like to know that things are happening whether it be that our government is working hard doing what’s right for us (sic), that the chef is cooking the dinner we just ordered or simply that the cash machine will give us our own money when we ask for it.
It comes down to expectations. We expect that these things should be happening and if they’re not then we want to know. If we know it’s not then we can work with it and react appropriately. However, when we’ve not been informed that nothing is happening - that is when we tend to lose it.
However, I am a firm believer it letting people know when something is and/or isn’t happening regardless. This way you don’t have to rely on unspoken expectations - everything is out in the open. For this reason, i can frequently be seen frowning at a plethora of apps and webpages that ignores this rule.
Did you know that the whirring sound that an ATM makes is not mechanical? Yup, I know you thought it was some sort of piston and pulley counting out your money but that sound is purely there to let you know the machine is doing something.
Now this concept isn’t new in technology; we’ve all seen a loading bar when installing a new piece of software. That’s there purely for us to feel comfortable that the system is working - it’s the same as the ‘swoosh’ you hear from your iPhone when your mail has sent.
I didn’t write this post to name and shame anyone but purely to highlight that designers and developers should never assume that someone is going to know something. Guide a user in using the product and for god's sake let them know something is happening. It’s important :)