Why is it that......?

.... no matter how many times you vacuum and sweep, no matterly how thoroughly you clean, the next time you move the couch or sweep under the rug, you find ANOTHER of those metal hooks that one uses to hang holiday decorations on the tree? It's like there's an infinite number of lost decoration hooks and when you pick one up, another one pops out of a small wrinkle in reality and replaces it. It can be March, July, Sept, even November. I've found two of them just this week while rearranging and shifting decorations and furniture.

There are lots of things in the universe like that of course. Some of the more common ones are:

Why is it that... no matter which lane you pick (at the market or on the freeway), it will always move the slowest?

Why is it that.... your mother always calls when you're just about to head out the door and your kids always wait to call until your favorite t.v. show begins?

Why is it that.... if your cat has the choice of yakking on the floor or the rug, they always choose the rug?

Why is it that.....the first pancake never turns out edible?

So, what other "why is it that..." can you all think of?