I once had a labourer on a job running a mixer for compo. When the mix was stuck he'd wham the barrel (running) on one side with a shovel then walk around to the other side and wham it from there. Repeat until bored. Good worker, but by 'eck he was thick. Once left him to dig footings on a sloping garden for a wall. Started the trench off for him to show him the depth I wanted. I went away for a couple of hours to do something else, when I got back the trench was epic. He'd kept the bottom perfectly flat and was up to about five feet deep as he'd dug further into the slope!