The reflex is to keep hammering the shutter button. Half-press, hunt, rack out to infinity, rack back, miss. We do it four or five times in a row, getting more irritated with the gear with every failed zip of the motor. It feels like the machine is deliberately disobeying orders.
It’s easy to forget that the camera isn't stubborn—it's just stupid:
"A five hundred quid lens can't tell the difference between a dark snail shell and the dirt behind it."
The moment you find yourself fighting the autofocus, drop the argument. Flick the barrel switch over to manual. Take your thumb off the button. Modern bodies have tricked us into thinking that letting the computer handle the focus is mandatory, but all it takes is one twist of the ring to remind you who is actually holding the camera.