One time I was opening up a mortise lock at our shop, and someone had already worked on it years and year earlier and it had the address etched in the inside of the lock body..customer was in the shop and he was telling the person behind him how he just moved to the area.
I poliety interjected and ask him if he just moved into, and I read the number..he was shocked and asked how I knew. I told him I recognize the lock!
Both customers were flabbergasted! I finish up the customer is so so happy impressed. I looked at him told him no charge, and welcome to the neighborhood and he walked off in complete awe. As soon as he left the other customer asked me how I did that. I told him, the address was etched inside. Both of us broke down laughing..I got two life long customers that day both think I’m incredible, and both bring up that story Everytime they come in