Humans usually do best in equilibrium. Where there is a balance of pain and pleasure, work and rest... in fact, all things may be in equilibrium by design if the human defines it as 'the "just right" amount'. However, this could be a bias where the human is not used to even the possibility of an alternate world with no work, school, e.t.c. So equilibrium kinda also has to assume the possibility that there is a pragmatic situation you can actually adapt to in the first place.