In maybe third grade I brought my collection of x-men trading cards as part of a sort of show and tell activity. It was in a sizable three-ring binder with those 3x3 slot cars sheets. I had a number of highly valued "foil/hologram" cards. The binder was gone when I got back from lunch. I was devastated and learned to never leave anything of value not locked up if I'm not watching it.
At work we have a kitchen/break room. I've had shit stolen from there a lot. Utensils, cups, bowls. Wash it after lunch, put it in the drying rack, come back in an hour to get it and it's gone. Once my department had a leftover pizza from an event donated to us. I brought in a baking sheet to reheat it in the oven for a lunch morale boost for the team because we had to work that weekend. The sheet, left in a drawer and not visible to any casual observers, was gone by Monday. That was actually the first item I'd had stolen there but I thought I was just s fluke.
I've literally bought upgrades and utensil sets for the kitchen (maybe people "stealing" my utensils just forgot to bring a fork, borrowed mine, and brought it home by accident?). Stuff like drying towels, soap dispensers + large refill bottles, a microwave food cover... all stolen. I'd keep getting frustrated with, for example, people leaving the sponge wet in the sink. I'd think "its been a year since I last donated something, maybe it'll be different this time..." and I'd buy an OXO sponge holder or something and within a week it would be gone. Everyone in my office, including secretaries and cleaning staff, gets paid at least a living wage with great health benefits. Some make well over 100k. I just imagine someone making twice my salary seeing a nice soap dispenser and taking it home... lost a good bit of faith in humanity and affected me way more than it should have.
I found a solution though. Whoever was stealing this shit couldn't deal with the shame of being reminded that they stole it. I started labeling the donated items using my organization's acronym with a permanent marker in big visible letters. None of that's been stolen. I was going to engrave my utensils/dishes but decided instead to look like an asshole and bring my own towel when washing my dishes, drying them immediately, and taking them back to my desk immediately.