The feeling of Flow becomes, in a sense, psychologically addictive, leading to Creative Courage
The concept of Flow was developed by Mihály Csíkszentmihályi in 1975. More here 
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YOUTUBE I_u-Eh3h7Mo TED Talk – Mihaly Csikszentmihalyi – Flow – 2004
The brain learns faster in a Flow State due to the release of neurotransmitters:
YOUTUBE aHp2hkue8RQ The Neurochemistry of Flow States
When a team is working together, they can enter into a Collective Flow.
Hyperfocus is a critical element of Flow. Chris Bailey recently released a book that explores this topic.