I recently drove (30m) to a park in Munich and then the Z8 wouldn't take a picture. Turned out I left the card at home
After about an hour, I was back with a card and got some nice shots.
But now I always double check that a card is inside a camera before I put it into a backpack.
I also check settings like AF, fps and that I do not have a self-timer or delayed exposure turned on (e.g. after a landscape shoot) when I go after wildlife. Sometimes I forget to turn off delayed exposure or set that camera to the wrong shooting bank. Best to check all this before the flying unicorn shows up and you only got one shot