It is good to be able to laugh at yourself and to admit your screw ups. I haven't done anything like that at least I don't think I did anything today.
One of the funnest things I ever saw was the tech who was doing an oil change and while he was doing it he was talking about how he was the only one in the shop who hadn't screwed up an oil change (we had been through a rash of wrong filters, double gasketed, loose drain plug, etc.). This was early in my business and the crew I had hired then in my ignorance almost put me out of business. Well he says he is the only one who hasn't screwed up. Then let the car down and proceeded to pump five quarts of oil into the car while we all watched it run out the drain plug he had forget to put in while he was congratulating himself. What a mess and what a laugh!