I realize that I'm probably being way over sensative to this but it drives me just a wee bit crazy when people "shhh" my baby. To me "shhhing" people (or children) implies that they are doing something wrong. And a 4 month old can't be doing THAT much wrong! Also, "Shhhhh" is not a soothing sound meant to calm a distressed infant...it's meant to quiet annoying movie talkers or possibly older children who have gotten overly rambunctious.
Anyway, just a small rant.