"No face which we can give to a matter will stead us so well at last as the truth." -- Henry David Thoreau, Walden, p. 217
I'm disappointed in anyone who voted for or still supports Trump. Putting politics completely aside, he suffers from at least three major flaws.
First, he is a liar and an exaggerator. None of us should trust a liar in real life, so why would we want one as president? Being an exaggerator may be great if you're a salesman, but a president should be a leader.
Second, he demonstrates the typical tough guy syndrome. In real life, you meet someone who's a tough guy and you know that they have major self-esteem issues (which is why it's no surprise that Trump, especially during the primaries and election, constantly referenced the polls, to convince himself and others that he's popular); typical big ego to mask small self-esteem, not what a true leader is made of.
Third, he exhibits an immature lack of realism, in that we can all see that we live in a globalized and further globalizing world (internet, more and more international travel, more and more international trade), yet he thinks he can stop the inevitable evolution of the world by putting us behind walls both literal and figurative.
All of these major character flaws exist without even having to get into binary liberal/conservative politics.