In order to “inhabit” a world, there must be a common bond between the “self” and the “world.” The world of Yetzirah is a world of holy emotion and the angels who serve Hashem with their emotional instinct abide there. Emotions are their mode and so that is their world. The world of Beriah is a world where the Divine intellect, the source of the holy emotions, radiates. Righteous people who served Hashem with intellectually generated emotions abide in this higher world, where the setting is one of deeper identification with the Divine.