cracking laugh this morning

A guy I know asked me to pop round to a house he's selling to look at moving a switch and socket in the garage,I arranged it for this morning as I intended to spend the day doing some jobs at home.Well I went and looked at it and there was a bit more to it than he thought,ok move the switch and replace a switch,all surface wiring no problem.There was a radial feeding 2 sockets in the garage and the lights were just taken off this with a JB,I fitted a fused spur and dropped a 3A fuse in,ok there now.He decides to swap a light in the house as he doesn't want to pay me for doing it(he's tighter than a duck's behind) he swaps it,turns it on and bang! It turns out it's a faulty fitting so back to B&Q he goes,he gets a new one then finds out that the short has blown the switch too.lol I,m looking around the house and there is a tv mounted on the wall,about a foot below it is a tv point and a twin socket,why? None of the sockets in the house are level and he's got these horrible led fittings in the dining room,apparently they were cheap on Ebay.
Anyway it turns out that he didn't ask me to do the electrics on the whole house as he had a mate who had a mate! everything in the house had to be done at least twice as they made a mess the first time,I asked if he'd got a cert for the electrics and he said he had,given the state of the garage wiring it's obviously dodgy,but he didn't have it to hand for me to look at.
The best bit was when I had finished,I gave him my bill for the work I'd done today and he said he wished he'd used me for all the work instead of the other guy,the thing is I've done plenty of work for him in the past and he knows that 1) I always do a decent job, 2) I don't rip him off. Plus I usually get the job done quickly for him,I wasn't supposed to be doing that job today,just pricing it,but because he needed it done before the estate agent came round I got it done.I wonder if he'll learn?