I was recently out with a friend and her kids. She's got two girls that flank the babes in age. The three of them are great friends. We were eating out and D and I got into a bantering match and my friend burst out, "Oh my gawd, will you two just stop! You're like two siblings bickering!" And then she tried to share a strategy as to how we could calm ourselves down and engage in a respectful way.
