We live in a crazy world, folks. A crazy world spinning through a crazy solar system in a crazy galaxy in a crazy universe. And then, just when you think you've got this "existence" thing figured out, the crazy arrives, breaks your glasses, steals your lunch money and pushes you in a puddle of mud.
Case in point: doing brain exercises may may actually accelerate mental decline. If you think you're going to nip that dementia thing in the bud by playing chess and doing crosswords and breaking out Brain Age 2 every morning, you're in for a tragic wake-up call. You see, keeping your mind sharp has the side effect of hiding symptoms of brain deterioration until it's too late to do anything about it. In a sense, you're so busy protecting you brain that you don't notice its decline.
I know what you're thinking. You're thinking, "C'mon, that only one crazy, bizarro, mirror universe thing going on in the world right now...everything else is completely and perfectly normal."
You would be wrong, my friend.