The theory of flow states that people are happiest when they are fully absorbed in an activity. This means that they are so engaged in what they are doing that they forget about time and feel really good.

Mihaly Csikszentmihalyi is a renowned psychologist who developed the theory of flow. He describes that the flow state occurs when a person is so engaged in an activity that they forget about time and become completely absorbed. It is a state of complete concentration and devotion.

In flow, the person's abilities are well matched to the challenges of the task. This means that the task is neither too easy nor too difficult - it presents an appropriate challenge. In this state, one experiences a sense of joy and satisfaction.

If the complexity of the task were beyond the person's capabilities, then the person would be overwhelmed. Conversely, if the task is too easy for a person's abilities, then he or she would be bored. Both can lead to frustration and procrastination. Therefore, it is all the more fulfilling for us humans when our own abilities and the complexity of a challenge are in harmony. Accordingly, it is always the intrinsic motivation, the pleasure of the activity itself, that is in the foreground.

It is important to emphasize that flow can occur in various activities, whether e.g. it is working, painting, making music, or even playing sports. It is not limited to specific activities.

In summary, flow is a state in which a person's abilities are well matched to the challenges of the task, giving a sense of ease and flawless progress that makes the person happy.