Tony (who has a birthday coming up): I don't want to turn four. I want to stay three and a half.
Tony (quite concerned): Because four year olds don't like to play with cars anymore and I still want to play with my cars.
Me: You don't have to stop playing with cars when you're four. Lots of older kids still like cars. It's OK.
Tony, visibly relieved, has nothing more to say. And all I can think is: Sweet Tony, you can stay three as long as you want. In fact, please do.