There are certain myths that the movies perpetuate: every one in ten people is employed as a hit man; your cell phone will always break when you need it most; if you hate someone, it’s really because they are perfect for you. Also, diapers are very difficult to use and liable to get you peed on, especially if you are a man. This last myth is being perpetuated at this moment by Life As We Know It, the Katherine Heigl–Josh Duhamel romantic comedy opening today. In the film, two people who hate each other (but, see above, are actually perfect for one another) must raise a baby together after her parents die. Inheriting a baby, especially owing to the sudden deaths of your best friends, is a big, life-changing ordeal, but, as in many movies before, no obstacle looms quite as large, or as odorously, as learning how to operate a diaper. That poop-catching device, used by hundreds of millions and accompanied by directions, has undone everyone from Homer Simpson to Tom Selleck and Diane Keaton, the latter playing characters who have, apparently, not watched enough movies to know the diaper pitfalls to avoid (don’t pull the tabs; be prepared for bad smells; watch out for pee). Check out this video slideshow for more movie moments in which full-grown people are undone by the ultracomplex diaper.