Because they belong to Mr. Phillips. and he sneaks in and takes them back when your not looking. He probably did not get his cut of the invention rights and this is his way of getting even. Might want to change your locks.
As for all you guys missing socks; I think the sock manufacturers make one sock so that it disintegrates to pieces in the washer and goes down the drain. This way you have to buy more and the sock manufacture makes more money. There is also a sense of incompleteness my life that is just not settled until I throw away the unmatched ones and only have matched ones left. It's a security thing, ya know. They literally sock it to you...
If anyone has insight about my mismatched gloves however, I'd like to know...