A famous Chinese Buddhist sage, Zhiyi, systematized from the Lotus Sutra ten basic life conditions. The first 6 are called the lower worlds because they are characterized by a passive approach towards life: Hell, Hunger, Animality, Anger, Humanity (tranquility), and Heaven (rapturous fulfillment of desire). The higher four worlds require an active approach to life: Learning, Realization, Bodhisattva (compassion), and Enlightenment.
The Humanity and Heaven, though happy, are relative happiness. The higher four worlds represent absolute happiness.