JUST SAYIN'.....

  I'm pretty sure Mother Nature fucked up with the  "kids cry when they're tired" thing. Crying looks like it is anything but restful or restorative. It would have been much more prudent and efficient to design the child to promptly become unconscious when tired. Just like the famous fainting goats do when they become over-excited. It's a win-win : child gets rest, the rest of us don't get annoyed. 

                                         .....Just sayin'.......