For instance, in our game we’ve got butterflies, and of course you need to massage butterflies to get butterfly lotion. And so we could make it so simply by clicking on the little fellow anywhere on the screen it would massage him, but that’s not fun at all. It’s useful and easy, and you could collect as much butterfly lotion as you wanted, but instead we make you work for it.~ Daniel Burka - Friction Can be a Good Thing: The role of gaming dynamics in user experience