I was in awe of an old vending machine I saw in the Caribbean recently. I didn't want anything but I spent a few seconds just pushing buttons to check prices. The segmented display read out the price the very instant I touched the button for the item. There was no perceptible delay for a bloated software stack running on some cheap processor that waits for too many bits over a crappy cellular internet connection. Everything needed was right there, between the hard-coded logic and me.