I once put my car keys on the roof of the car and forgot them. When I checked in the evening whether all my keys were there, I searched feverishly. Actually, I could have remembered in my mind what I had done, but because of the panic I just looked everywhere. And then I was glad that the car key was still on the roof. Since then, every time I've used the key, I force myself to see where it is and to do so immediately. If I see that someone has lost something, I leave it in place because that's where the owner would expect it the most. Once I saw that the neighbour had left her key outside. Then I rang the bell. Because then you always have to imagine that someone could break into the house. Trying to always remember, I think, is a good thing.
This is a good lesson - pain helps remind us. Someone who has lost money out of their pocket, always remember the even whenever they put more in.
This is the first time I have lost my keys and I still think they will turn up somewhere. We have a lot of stuff around at the moment in the house, so it could be anywhere, Unless it slid out of my jacket pocket while getting in the car somewhere....