My understanding of the Id comes not from Freud, Freudians or even Freud-popularisers, but from Forbidden Planet.
Here is the Id-monster, raging away, and the crew considering a cast of its foot.
It contains all the Bad emotions boiling away, held down by the Ego, the conscious being, and the Superego, or parent-figure. Or, the man is the Ego, the angel on one shoulder the Superego, the demon on the other the Id. I culled this quote from Freud’s New Introductory Lectures on Psychoanalysis from Wikipedia:
It is the dark, inaccessible part of our personality, what little we know of it we have learned from our study of the Dreamwork and of the construction of neurotic symptoms, and most of that is of a negative character and can be described only as a contrast to the ego. We approach the id with analogies: we call it a chaos, a cauldron full of seething excitations…. It is filled with energy reaching it from the instincts, but it has no organization, produces no collective will, but only a striving to bring about the satisfaction of the instinctual needs subject to the observance of the pleasure principle.
Against that was Carl Rogers’ image of the potato, in a cellar, putting out a shoot towards the tiny, spiderwebbed window- trying to be the best potato it could be.
It makes no sense that we should have an Id, roiling away, needing held down, though Freud was a scientist by intention, he did not merely make up his observations. It makes a sort of sense in a created world with Original Sin inherited from our First Father, but not in a world where we evolved. And- that is what it feels like, sometimes, an Id, a monster, an enemy.
Unless the suppression makes the id into a monster, where unsuppressed it would serve our needs. So where would the Suppression, the real monster, come from? The conditional love, the negative love, the tyranny of the Normal which makes us need to pretend to be other than we are- so that we can live together without killing each other, so that we can work together obeying orders. So that my father could obey orders, and fly over Germany as the rear gunner of a Lancaster, in order to bomb it.
And now our myths free us from the suppression. Max goes where the wild things are, and becomes their King.