Wagner's MBA Law of Overhead Bin Storage in Airplanes

Wagner's MBA Law of Overhead Bin Storage in Airplanes: Given normal gravity, your carryon bag will often fit if you turn it upside down, with the rigid side up (i.e., wheels up) and the soft side down. Gravity compresses the bag. Plus there is often a dip in the bin that is not otherwise filled. Gravity will make it fit; this seems perfectly obvious, but passengers and flight attendants often seem grateful when I share the information.