1. People hate Hillary Clinton. Haaaate her. No, you think I'm saying they disagree with her politics, but you don't understand; many literally think she is an evil person, and they want her to burn in hell.
2. Most people don't really like Trump. They are bothered by his comments, his style, his bombastic way of living, etc. But they also don't think consider him racist or particularly sexist.
3. They are so fucking tired of identity politics. Oversensitivity, calling everything "-ist" to win an argument, trying to tie racism into everything, debates over "privilege", etc. I would be so bold as to say that if the left doesn't tone down the identity politics Trump will win a second term. Full stop.
4. They are tired of being spoken down to, told that they're not part of the America that matters, and they have a serious chip on their shoulder. It seems to them like they're being told there's only one "right" way to view the world, and it's not theirs. But they like their way of life, they don't want yours, and want politicians to generally leave them alone and let them be.
4a. The worst way to exacerbate that all of these things? To insinuate that people who vote for Trump are doing so because they're -ist or dumb or ignorant. Hillary Clinton did just that, and I saw more on Facebook about Hillary's "basket of deplorables" comment than about anything else in the election. I sometimes wonder if that was the tipping point to Trump for many middle-of-the-road voters in rural America
4. They are sick of "coastal elites" running their lives and pretending like everything is OK. Small towns are hurting. A lot. Realize the median household income in the town I came from is <$30k and the average number of people in each house is 6, and you'll understand why people are livid about Obamacare increasing insurance costs (after so many promised it wouldn't do so). Things are tight, taxes are scary, and when the seemingly rich, out-of-touch people are hand-wavy about increasing the single biggest expense by 50% when you're barely making it (food/housing is cheap) you get the hatred for Obamacare.