Because the powers of the big bang started to decrease
the universe started cooling down.
Through the cooling of the universe energy was turned
into matter. In the process much pure energy was used which worried the
energetic-beings about their own growth (energy can not be lost it's only
transformed).
With this the most (first) primary emotion was
originated, mortal fear. Because the energetic-beings their growth was
obstructed. The energetic-beings were frightened and therefore tried in every
way possible to reassure their growth. At first they joined but sadly they also
turned against each other (why slow down
if you can use another energetic-being for growth?). This fear of
transiting was the very reason that the energetic-beings obstructed each others
growth.