Changing a tire on a car.
Last time I had to do this was when my friends car got a flat on the way to a guys weekend. He was on the phone to his dad going "do you have the number to my breakdown service" while I'm like "Do you have a jack?" Yes. "Do you have a spare tire?" Yes. "I can fix this, trust me." Ten minutes later, I'm tightening the final bolt with a "That should do it", the guys give me a "Should?" I give the bolts and unnecessary additional tighten, wipe the sweat from my forehead(despite it being winter) and go "yep". This while all the while fighting the rigours of sleep deprivation.
But I simply could not have had that slight against my MANHOOD of having a breakdown service guy coming out to 3 guys and not one of them knowing how to change a tire.
Of course later on it was a case of "yeah we could have done that, its easy". Uh huh. So why didn't you do it and why were you asking for your breakdown service?