In this fascinating talk from the TED conferences last year, Mihaly Csikszentmihalyi talks about the creative process and describes the ideal state for maximal creative productivity.
It seems really right to me that your mental state when engaged in any sort of creative work should be a function of the difficultly and the skills you have to overcome that difficulty. It also seems right that the most rewarding state is a balance between the two, work that is either too difficult or too easy can be respectively frustrating or boring. It also seems to me to apply to all types of work where one starts with a metaphorical blank sheet of paper, not just creative work in the narrow sense.
I think that this description might also apply to working in teams of people. We all know that feeling when a team is working really well together, at the height of its powers vs a team which is struggling to cope with the challenges in front of it.
In either context this is a valuable principle to live by, and if we maximise flow in our professional and personal lives then we stand a good chance of fulfilling our potential……