One of the most mutually beneficial states that two people can achieve is symbiogenesis, where they take such pleasure in each other's happiness (and displeasure in each other's unhappiness) that they start viewing each other's interests almost as their own. The more strongly this happens, the closer the pair is to being a single, two bodied organism, working towards a common set of goals. One remarkable benefit to such a state is that it allows for a level of optimal allocation of resources ...