I couldn't turn it off this afternoon.
I kept stalling it on the lush grass I was cutting, then when I wanted to turn it off the switch didn't work.
I asked a neighbour how to turn it off and my idea to disconnect the (flat) battery was the received wisdom.
Walking back down the side driveway I pondered jumping back on the mower and completing the front mowing before I shut it down because, sure as shooting, if I couldn't stop it now, I wouldn't be able to start it when I needed to during the week to cut the front grass.
By the time I got back home the mower was coughing to its demise. There was still petrol in the tank.