you must be the dodgy plumber that's ten minutes late.
Just remembered I've got this customer I've done 3 jobs for and without realising it or planning it I've been on time to the nearest second each time. He's the type that notices and mentions it each time. I always use the line "it's more luck than judgement" but now I feel I have to keep it up.
Like there's this other customer. She's so ridiculously over-praising you'd think I was Jesus. "I'll tell all my friends, you're amazing" etc.. It makes you feel you've got to do an amazing job to live up the compliments.
Both of those make me think if you want to manipulate someone into going the extra mile, doing something for nothing or pulling out all the stops don't do it by criticism or nagging. Do it with huge amounts of undeserved praise. Works every time.