But the reward of a successful collaboration is a thing that cannot be produced by either of the parties working alone.

... But the reward of a successful collaboration is a thing that cannot
be produced by either of the parties working alone. It is akin to the
benefits of sex with a partner, as opposed to masturbation. The latter
is fun, but you show me anyone who has gotten a baby from playing with
him or herself, and I'll show you an ugly baby, with just a whole bunch
of knuckles.
-- Harlan Ellison