So I spoke to my formerly Trump supporting father, who now wants to see him impeached (as I noted earlier in the thread). I asked him why he supported him, in more detail. What it came down to was essentially, he didn't want to vote for Hillary and because he hadn't followed much political coverage during the campaign, he didn't realize until after the election how terrible a candidate and human being Trump was.
He had watched the GOP convention, which was one of the few times Trump was very highly scripted and on message, and thought Trump seemed 'fine'.
He has always wanted a business man as president (his own business bias, being a real estate guy himself). Now he admits that he didn't realize that most of Trump's money came from 'salesman' work/name licensing deals rather than as my dad put it, ACTUAL business.
He said that he was immensely impressed with Trump's children, which he assumed reflected well on Trump's character. Then he joked rather bitterly that he's now seriously wondering if those kids are really Trump's, or all the kids are secretly horrible/stupid as well.
He hadn't watched Trump in any public appearances except the debates and brief clips...no interviews etc. As he said on the phone (paraphrased from multiple minutes of Dad ranting), 'That guy is just a flat out IDIOT, and there is obviously some kind of major psychological problems, too. He can't say a coherent sentence and he doesn't know anything about ANYTHING!'
When I pointed out that Trump had not changed his behavior at all since the campaign, and that all these characteristics were apparent back then, he just admitted he hadn't bothered to do his homework at all. He was, in fact, not even aware going into the booth that a very good, older school, conservative candidate (Evan McMullin) was on the ballot for him to consider.
So, there is some detail to answer the OP's question, from a data point of one miserably sorry independent voter.