The flow is something that has been studied since years and I find this mind status important when you are working with other people. You do not need to be a team lead to think about it, it’s just to understand how people is behaving and how they react.
I find this picture useful to identify generic behavior of a given person, so I can understand how s/he uses to be, and for people who is working with me for more time, it helps me to understand how they are.
Other interesting review is here, (sorry, it’s in Spanish).
For group behavior I prefer Belbin team roles, for understanding individuals, this is more convinient.