and this is how you will wear out your transmission

 

i had an auto for 40k miles, and i shifted for fun a lot. yes, it adds wear. but i never had a single problem. everyone says wear this wear that, like it matters. its all electronically controlled so you cant really mess it up or blow the engine unless you're going downhill. you can enduce a downshift by just stepping on the gas harder. so is there really a difference? who knows. but hey "it adds wear" so do it at your own risk. we're all just taking stabs at it really.