Oh, if I had a nickel for every time I had to tell one of my kids to "get your finger out of your nose." Or...pick up your shoes clean your room don't put your feet on the table use your inside voice don't hit your sister don't yell at your brother etc etc etc
So...I ADORE these signs from John W Golden that say everything that needs to be said (and it bears mentioning here that my mother often signed the notes she wrote me as a child, "the managment.")
This one would be great in my kids' bathroom:
...and my all-time favorite (if I had a bar, this would go over it)...
...among many many other awesome signs that he's got listed on etsy. Oh, how I wish I could afford one or five right now!