D.M.
Actually, if she saw you cry, you may see some difference, at least for a time. I remember once I said something that just wasn't right to my oldest, because he was being so difficult. Then I just sat down on the floor and said, "I am sorry, I shouldn't have said that. But when you act like this I just don't know what to do." He was cooperative for the rest of the day!
Not that it works every time but when they see you really, truly, sad about their behvaior, it often gets through.
I am trying to think of a defeat that would make you laugh. Hmmm...when I was trying to potty train the same son and was letting him run around without pants, and he walked up when I wasn't paying attention and said, "Here Mommy" and put something in my hand. It was poop.
Son #3 is a baby. Son #2 is only 2, so the stories aren't funny yet. ; )