Heidegger argues that skilled coping, when we engage with entities as ready-to-hand, is our primary way of engaging with the world. Sometimes, though, our skillful coping is temporarily disturbed. When this happens, we encounter entities as unready-to-hand. When we go from smoothly hammering to having difficulty, our experience of the previously ready-to-hand entities changes: we experience the hammer, nails and board as failing to serve their function appropriately.