On a recent inspection tour of the kitchen, the staff were exhibiting the new kitchen faucet that had just been installed over one of the basins. It has an extra feature, they explained in tones of admiration. There is a button on the side that you can press for more water pressure.

Now, Dr. Boli thought himself quite familiar with the workings of faucets, at least from the point of view of the occasional user. He had thought there was a perfectly serviceable pressure regulator in the faucet handle.

Yes, one of the scullerymen explained, but on this faucet, you can turn the pressure up to full, and then you can push the button and get more pressure.

Here Dr. Boli smiled and kept his mouth closed, because good scullery staff are valuable, and if they are made happy by spending a little too much money on a faucet, then that money is well spent. But you, our readers, know that there is no such thing as “more pressure.” It is not possible to open the valve all the way, and then push a button and get more pressure. It is, however, possible to restrict the flow to less than full until a button is pressed, and then remove the restriction. This is in every way less convenient than a simple valve that can be set at any arbitrary point from completely closed to completely open; it means that turning the faucet on full blast requires two motions now instead of one. But it is a feature. The faucet-seller can point to that button and say, “Here is something our less expensive competitor cannot offer you.”

Absorb and understand the lesson of the faucet with the “more pressure” button, and you will be fully qualified for a career in marketing.