Heard one like this from a friend; members of a village hall asked a fella to repair a dent in the hall's bell because it didn't sound right. Said fella looks at it for five minutes and whacks it with his hammer, job done, bell working perfectly again. "Five hundred quid please" asked the bell expert - "You were only here five minutes!"
Yep, million pound yet, engines wont start, every engineer in the area looked at it and couldn't fix it. Old fellas who runs a boat repair shop gets asked to look at it. He studies the engine for ten minutes and then turns a valve. The engines spring into life. How much they ask, £10,000 he replies. That's a bit steep they say, we will need a breakdown of costs.
For turning the valve £10
For the experience and knowledge knowing which valve to turn £9,990