This document discusses designing for emotion and flow. It explains that flow is a state of intense concentration where one's attention is fully focused on an enjoyable activity. Flow occurs when there is a balance between the perceived challenges of a task and one's skills. The causes of flow include having a clear goal, receiving immediate feedback, and facing an appropriately challenging task. Designers can aim to create flow by removing distractions, providing feedback, and balancing perceived challenge with users' skills through intuitive interfaces that adapt over time. Flow tends to improve experiences and lead to positive emotions.