1. It was blown to the ground by the wind and was mistaken for garbage removal by family members.
2. Be hidden by small animals at home, such as cats and dogs.
There was a thread loose in the clothes, and then it fell off.
It was worn backwards and taken away as garbage.
If you are not sure what the situation is, you can try to investigate. If you still can't find it, you can ask your family if you have seen it, or go to a nearby garbage collection station to look for it. If you still can't find it, it is likely that someone else took it by mistake or left it outside.