This one has been bugging me
You know how calendars always hang better in the first few months of the year, because the top part of the calendar has fewer pages, so they don’t curl down around the tack you used to hang it on the wall? They should print calendars so that the last half of the year is printed upside down, so that you can flip it over and have a satisfying calendar hanging experience all year.
There. I finally got it out. That idea is free to anyone who wants to use it.