Reminds me of a funny story.
Few years back a friend had a very old mini. Think it was made around '63 and a complete wreck but nonetheless it was his car, quite rare and delicate and he was very particular about it.
Anyway, one day he agreed to lend it to someone as their car was off the road. He gave them a long lecture about double de-clutching (Magic wand gearbox), not travelling above 45mph, not slamming the doors (Cable door handles), slowly round corners (Cross-plies), leaded petrol only etc..etc.
The car was returned after a week, with thanks. The guy then said "Oh, by the way, the gearbox makes a strange grinding noise at about 50mph, but it goes away when you reach 65mph.."
It was a wind up but I have never seen anyone go that particular shade of purple before and never seen anyone else run quite so fast!! Took him a week to calm down about it, too!