When I had a garage in south Manchester we had a competition to see how terrified we could make a customer if, for example, we dropped them back home or at the train station. We called it the "motor trade driver of the year award".
A near empty whiskey bottle that had to be moved off the passenger seat as they got in was the usual starter, after we'd dabbed a good bit on our collars. Best (worst..?) was a woman who jumped out at traffic lights and appeared back at the garage an hour to remove her car whilst screaming abuse at my partner.
We were young and making far too much money, but I admit to chuckling to myself now at the memories of some of our antics. Only our own garage hacks were damaged, no people or animals...
My partner was asked if he could make a stop for a guy to post a letter. So he mounted the pavement and crushed the passenger door against the pillarbox and asked if the customer could reach the aperture OK, without getting out and getting wet, for example....
Then there was an old brake pedal we kept in a Citroen, which had a rubber button affair for a brake pedal. We'd find a hill and pretend it had snapped off as we picked it up off the driver's side floor, rapidly gaining speed. Unless you knew some Citroen's had this bizarre rubber button it looked very convincingly as if the brake pedal had snapped off.
Terrible things we did, terrible. Probably have some sort of claim against you nowadays, amazingly we never did get any real flack.