In my case, I blame cats. I had one run off with an entire drain assembly while making strange noises. I figure if he can steal that, then they can be blamed for all the missing stuff. I have one who loves wires - not usb or cords, but the wires I use within projects. I've learned to give him a piece to play with when I start so that he has his own and doesn't steal any that I have cut to specific sizes.
I'd love to blame mine on cats. Unfortunately, I am not a cat so I cannot blame a cat.