Flow, with its many definitions ranging from a fully engaged brain to the movement of organic liquids, seems widely desirable provided that the initializing elements are also desirable. In this case the focus is on flow as a mental state. I imagine the meta state of flow manifests as optimally implemented intelligent targeting with respect to the many targeting elements (such as time, interactive variables, desired outcome).

As a function for a single human confined to a single mental universe, it might be represented as such: Flow(Flow).

“Flow is the mental state of operation in which a person in an activity is fully immersed in a feeling of energized focus, full involvement, and success in the process of the activity.”

Food for thought: Consider both the motivations and social implications of directing, redirecting, and misdirecting the state of flow in others. Certainly, the most optimal distraction is one in which that person is wholly occupied, and what better than to have them in a state of flow doing exactly what is wanted.