On the side of this box of McCann’s Oatmeal here it says: “Tip: Add liquid to oatmeal a few minutes before cooking. It will cook faster.” Now, I can see the benefits of doing this in terms of energy conservation. But the fact is, I’m not going to get my oatmeal any faster, am I? Sure, it’ll spend less time on the cooker, but the amount of time I spend preparing it will be the same, or maybe even longer.
This tip seems related to that recent finding that people were irrationally much more tolerant of an increase in shipping fees than the same-sized increase in the price of the good being shipped.