Everyone else is weighing in on their personal politics so I might as well do the same.
I first registered to vote in 1968 and I registered as a Republican. Not a lot of deep thought went into it - my parents were Republicans and Dwight Eisenhower was one of my heroes. At the time, I thought the Republicans would be more careful with my tax dollar.
As time went on and the Republicans became more and more conservative on social issues I wasn't as in tune with them as much. But, I didn't want to be a one issue voter and conventional wisdom said you needed to be a Republican to have someone to vote for or against in the primaries so I stayed.
By the 1980s, I worked for a Fortune 500 company. The employees at my company were treated well and what was good for business was good for me, right? So I stayed a Republican. Fast forward a few years and things began to change. Pension plans were frozen but unless you were making significantly more than I made, you couldn't afford to put enough into your 401K to make up the difference. Premium payments on our health insurance went up and up but the amount they would pay shrank. Raises became smaller and smaller and then went away altogether. The company sold my part of the company and we were shifted from company, to company, to company - 6 different times. Each time, the bigwigs made a boatload of money and the rank and file employees got the shaft. Even so, I stayed a Republican - even though I voted for fewer and few Republicans - until about 5 years ago.
There were a few straws that broke the camel's back:
1) The constant strangulation of the Oklahoma public schools by the Oklahoma legislature.
2) The emergence of people like Sarah Palin in Republican power circles.
I'm not sure if I've posted it here, but I loathe Donald Trump. I've voted in every Presidential election since 1968 and he is the only candidate that has run that has absolutely no redeeming qualities - no integrity, no honor - nothing.
You say his policies have been good? Maybe if you had a lot invested in the stock market he is. But if you can't afford those luxuries, he hasn't been good for you. If you want more air pollution and more water pollution, he's your man. If you are a racist who has privately fumed at what you call political correctness, he's your man. If you are a guy who wants to grab women who don't want to be grabbed and suffer no consequences, he's your man. If you don't like public education you love the person he put in charge. I could go on but you get the message. History will look back on DT as the worst American President by far.