All three kids are watching the TV while I cook dinner. A few minutes before I'm finished I go into their room...
Me: Turn the TV off when that show is finished, dinner's nearly ready.
Kids: Okay.
I go back to the kitchen and finish things in a few minutes. I then return to the kids to tell them dinner's ready, only to find the TV still on with a new show.
Me (slightly outraged): I told you to turn the TV off at the end of the last show. Why's it on now?
12YOS: We turned it off, but 10YOD turned it back on again.
Me: Why didn't you tell her to turn it off after what I said?
12YOS: But didn't you know? I'm unreliable!