The essence of idolatry is taking a heavenly form and corrupting it, bringing it down to the physical realm.
But idolatry takes this notion one step further.
Not only is a divine construct brought low, the converse occurs as well: An earthly entity is elevated to a lofty position.
Man himself, in various ways, becomes an exalted figure, an object of worship.
When our sages say that “when someone becomes angry, it is as though he worships idols” (Zohar, Bereshit 27b), or that “anyone in whom there is haughtiness is as one who worships idols” (Sotah 4b), they are making this same point – that a person can deify himself.
A person deifies himself when he rejects bounds and limits and begins to consider himself, to a certain degree, the king of the world.