Good points well made. An interesting second-derivation of this is with co-founders. Two (or more) people who share a goal can spur each other on via internal

Good points well made. An interesting second-derivation of this is with co-founders. Two (or more) people who share a goal can spur each other on via internal competitiveness & a symbiotic pattern of compensating for dips in the other's discipline or willpower. For example I'm sure neither Lennon or McCartney would have achieved half of their combined output.