There are probably thirty words I repeat more than one hudred times each day. "No, Yes, Stop, Ok." For my four year old daughter there is one phrase she uses more than anything else. "What did you say?" As in "I wasn't listening to you talk to me even though I'm standing ten inches from your mouth as it spews what I should interpret as gospel, what did you say?"
When she first began asking this question my wife and I - foolishly - began repeating ourselves to her and once she learned that, there was no incentive to listen. Her incentive was to direct her attention to whatever she was doing and then when she needed to know what we were saying she could simply ask us again, because we were - did I yet mention foolishly? - repeating ourselves.
Our four year old had mastered moral hazard and it was at our expense.
Now we're trying to break that habit but it certainly isn't easy and has certainly taught me about the moral hazards of parenting.