Donald Trump is socially awkward.  I see it in his speech, his limited ability to observe things and express what he observes in words that are "adult" vocabulary words, words adults use.  Trump is child-like, really.  It is not a fault, necessarily, except that his base sees him as their savior despite this short-coming.  It is a serious flaw for the President of the United States, for sure. 

Trump has little ability to truly connect with people, and money is his way of compensating for this weakness.  People always defer to a rich man with money, and are willing to ignore the rich man's faults if he sowers them with money.

The bottom line is that Trump is Immature.