Twenty years ago I was told that if I didn't do a better job cleaning my teeth I soon wouldn't have any. Since then I have been a champion brusher and flosser and user of interdental brushes in three different sizes - which must make me the ideal customer for the smartest of all smart toothbrushes, the new Oral B Genius 9000.
To use the toothbrush you have to attach your phone to your bathroom mirror at mouth level so that its camera can keep an eye on you as it takes you on a "28-day plaque journey".
As I brushed, the screen lit up telling me which bit of my mouth I was working on. This might have been smart, only I knew the answer already. It timed my brushing (a task my own electric toothbrush does efficiently) and while it did so distracted me from the job by telling me (incorrectly) what the weather was like outside, and what was happening in the world.
"Impressive!" it said when I was done. Again, this might have been nice, only I'm an adult, and therefore no longer need congratulating on having brushed my teeth.
The data from my brushing was duly logged, against which every future act of brushing could be compared - turning the oral hygiene routine into a fun competition against myself. I shall not use the app again. The five minutes a day I spend cleaning teeth are a time of relative calm, a phone-free oasis. I am going to keep them that way.
Yet this smart brush is almost certain to be a success, just as the previous versions have been. According to Procter & Gamble, 250,000 people use its Oral B app, evidently believing that Bluetooth leads to white teeth.
The giddy growth of smart technology is both easy to understand and a mystery. The growing supply is no surprise. Manufacturers make this stuff because they can... On the demand side it remains a puzzle. The fact that people are so willing to pay over the odds for non-solutions to non-problems is the best evidence of the irrationality of the consumer the market has yet provided.
It is not just the smart toothbrush that people are falling for. A friend tells me rapturously how her smart Elvie pelvic floor contraption, which calls itself "your most personal trainer", has changed her life. You do the exercises, while the matching phone app tells you how you are doing and allows you to compete online with your friends. Fitbit and Jawbone have already turned half the population into competitive walking bores. Oral B and Elvie take it one step beyond.
Less indelicate but no less inexplicable is the smart clothes peg, possibly the dumbest bit of smartness so far. Peggy, being tested in Australia by Unilever, is a plastic peg containing a thermometer and a hygrometer that sends messages to your phone that say: "Hi Lucy, rain clouds are on the way, let's dry the washing tomorrow."
The company is heroically pretending that Peggy will allow parents to spend more time with children. This makes no sense as the main thing that keeps parents from children is not pinning out the washing on rainy days - it's staring at their smartphones.
Superficially more promising are smart umbrellas and smart wallets that discourage you from losing them by reminding you every time they stray too far from your phone. Yet these sound like a damned nuisance - whenever you leave your umbrella inside your own front door and go to sit on the sofa, your phone tells you your brolly is out of radius.
The most unwelcome "advance" of all is the smart tampon. This is a normal tampon attached to a wire that connects to a sensor clipped to your underpants. Every time the sensor thinks it's time for a new one it alerts your phone. I can't imagine why anyone would want their body to be wired up in this way and, in any case, there is no need. Women already have two methods of knowing when to change tampons: looking at their watches and listening to their bodies.
The more I learn about the Internet of Things, the more I think I've slipped into a world of make-believe. I've just watched a slick video about NotiFly, an "invisible user interface" that will tell you when your flies are undone, which I would have sworn was a spoof. Yet the credit at the end said Accenture Interactive - and they are not best known for their sense of humour.
The giddy growth of smart technology is both easy to understand and a mystery. The growing supply is no surprise. Manufacturers make this stuff because they can. The technology exists. It is quite cheap. And thanks to Kickstarter etc, there is no shortage of suckers happy to finance it.
On the demand side, it remains a puzzle. The fact that people are so willing to pay over the odds for non-solutions to non-problems is the best evidence of the irrationality of the consumer the market has yet provided.
If we want such smart gadgets, we must be dumb. And not only that: Smart technology is making us dumber. If we no longer have to remember to do up our flies, or look at the sky before putting the washing out, and if our favourite conversation is who walked/ brushed/squeezed for longest, our brains will soon become in far more urgent need of exercise than our pelvic floor muscles.