Can you think of any urban paradoxes?

The one I came up with was the Why Don't You theme tune. Even as a bairn, I was struck by the fact that if we had turned off the television to go and do something else instead, we wouldn't have heard them tell us to turn the television off and so we'd be watching the television, but then we'd hear them tell us we should switch off the television to go and do something else instead but .... etc.