But karma is sticky and has lingering effects. After deciding the realm of rebirth, it furthermore brings about the kind of body we get, into which environment we are born, and which kind of motivation we live by. As a human being, however, one has all controls in one's hands. Having a solid body and being able to know what is useful or brings harm, one may avoid sowing the seeds for eons of impermanent happiness or deep suffering in the four non-physical realms or for shorter periods of dullness as animals. Most important is the realization that this is no alternative to liberation and enlightenment.
Gods fall down again.
Half-gods are jealous and fight. Animals eat one another. Ghosts are always frustrated and hell beings always suffer. Even humans have the four basic problems of birth, old age, sickness and death. Also, the best years of one's life are not without the difficulties of getting what one wants, of avoiding what one doesn't want, of holding on to what one has, and of having to arrange oneself with what is unavoidable.