At his primary school my eldest son, now in his middle thirties, was in his classroom one day when the teacher announced that something had gone wrong and the school computer (a BBC Micro) couldn't print any more. My lad, about seven years old at the time, put up his hand and asked if he could have a look. Ever keen to encourage inquisitiveness the teacher agreed. He switched off the computer and printer, removed the printer lead, blew in both ends and switched everything back on. To the utter joy and amazement of his teacher it all worked.
We had a CPC6128 at home and even at that tender age he'd learnt that with faults like that it was usually the bit in between that was the problem.
I've never been more proud!