The core Trump dissonance is that he's an elderly man who possesses the outward appearance and trappings of adulthood—and who occupies the public role we most strongly associate with adulthood—but who is on the inside predominantly infantile.
The president, if anything, exhibits a characteristic inability to see much beyond his own ego preoccupations. He appears to have no real friendships, habitually belittles those he sees as weak while denying any weakness of his own, and is perennially insecure, desperate to bolster his ratings, numbers, and stats by bending the facts to assuage his fears; he has little demonstrated capacity to joyfully laugh at himself (or laugh at all), and has professed to being uninterested in self-reflection and insight; the only problem he seems genuinely interested in (and truly capable of) solving is the chronic threat of his own waning relevance, and his guiding moral principle is that whatever works to make him 'win' is the right thing to do.
Trump's cognitive and psychological maturity deficits explain much about the jarring effect of his appearance and the strong reaction he provokes. Thus, beyond the dissonance and shock of witnessing someone so childlike in a position of truly terrifying and awesome power, the underlying fascination and dread of Trump's presidency emerge not merely from our sense that we don't know what he will do tomorrow, but also from the sense that he doesn't know that, either."