Murphy's Law of Diapers

Why is it that my children love a fresh clean diaper to poop in? Why can't they save the quarter and poop in the old one? Probably because they don't care about quarters. Come to think of it, it is probably the same reason that the day after I wash all the walls, Aly thinks it is a good idea to kick the wall with her patent leather Sunday shoes, filling the wall once again with dirt and black marks.