To respond to another comment you just made, it is not "the" driver, as in the only thing that makes me sad. It is one of the big ones. Modern politics and the loss of American mythology broadly make up the remainder. These are all arguably intertwined, of course.
Let me first correct my statement, it is a little too broad. In my circle of family and friends, I can readily identify maybe three people, one of whom is now passed, who I think of as Christians in the biblical sense. That is to say, their actions seem to closely reflect an honest attempt to answer the question "What would Jesus do?" The vast majority of Christians in my family are Evangelicals, though, and to be fair this is who I was really thinking of. They like to ask that same question, and then answer it "See Leviticus."
Why do they make me sad?
Because they are judgemental jerks who pretend that the Bible is the most important thing in their life while simultaneously giving uncritical loyalty to a man who is the closest embodiment of an antichrist that I've encountered in all my years.
They have tried to declare ownership of the word "patriot" and defined it as loyalty to their faith, while making a mockery of it at every turn.
They have declared a huge swath of their fellow Americans as evil, not someone to be disagreed with but someone to be bullied, kicked out of the country, or worse.
They make me sad when they try to talk me into hating immigrants, or minorities, when they piously say they cannot in good conscience be associated with the few people in our family who are openly gay, when they pretend to be oppressed by The Alphabet Mafia, when they act all righteous up until the moment when someone close enough to them (like their own child) runs afoul of these 'values'. And even then, more than one of them have disowned their child instead of moderate their approach to faith.
It is corrosive, antisocial, and they cannot seem to stop themselves from dragging everyone else around them into the mud. All I have ever wanted is to be predominantly left alone in my beliefs but loved by my family. I don't put conditions on my love, I am sad when they put conditions on theirs.