I thought of caffeinated soap around the first time I understood that nicotine can be absorbed through the skin. I considered patenting the idea, but realized that if the product went to market, some idiot somewhere was going to have a get rich scheme: put baby in little baby tub with caffeinated soap, leave baby soaking in the water and suds for hours until it suffered some problem from the caffeine. Then, I'd be sued into oblivion. I believe that they now make caffeinated soap - it's more of a novelty type item. I'm guessing the big companies haven't chosen to incorporate it into their products for the exact reason I realized I wasn't going to make money.
In 1st or 2nd grade (around 1971), we were making pinwheels in class. I suggested - "if you make a little pinwheel and put it in a tube and suck the air through the tube, it'll make the pinwheel spin." "That's right Thomas." "Couldn't you make the pinwheel out of razor blades and attach it to a vacuum cleaner? It would suck in your hair and cut it all at the same length automatically." "Don't be silly, Thomas."
F You! The Flowbee hadn't been invented yet. In fact, it wasn't invented for over a decade after I suggested the idea in 1st grade. Had I one of those encouraging teachers who helped students pursue their ideas, I'd probably be retired by now.
When they first started putting RFID chips in credit cards, and before they started putting them in wallets, I realized that you could weave a metal mesh into a wallet to create a faraday cage, protecting your information. Too late on that one.
And, when Tasers first came out, I realized that you could do a similar thing to clothing - weave a metal mesh into the clothing and you'd be protected from tasers. It's expensive to patent something. As mentioned above, most patents are pretty useless. Quite a bit later, someone patented the idea. Big deal, I thought. He wasted his money. WTF??! The US Government wants some of them?! They have a use for them???! Darn it!!
One of these days, something new will come to me. I just want to own a couple of patents.