I stopped caring when I was pretty young. I realized early on that people fail to consider the consequence of their actions. Myself included. We often merely push forward in some awkward social competition where the outcome doesn't really mean anything of value. So what do you do for fun when the people you know are good but they keep putting themselves into failure loops? Or their beliefs are out of touch with the reality in which they live? You seek out an activity where you're with those you really care about but may not have a parity of stuff to bring to the proverbial table of conversation. You ride motorcycles.
And when the idiots who can't put their cell phones down long enough to drive without crossing center lines or fog lines cross your threshold of tolerance, you trade those motorcycles for a highly visible truck. Because then at least these fools won't kill you.
Somewhere along the timeline between trading motorized two wheelers for human powered two wheelers I had a pretty good bout of cancer. But death never was a personal fear of mine. It's once you have a family that things begin to change. You're living for others more than you are for yourself. So you want to live for those who matter to you and because you matter to them. Your life really isn't yours anymore. And what you do care about changes. Or, I should say, you begin to care about things. You realize family is the most important entity you can care about and opinions, not so much. Not that opinions ever meant that much even though we like to think ours are "new and improved". (My personal inner circle is partly comprised of people who vehemently oppose my political views yet we have been there for each other in the worst of times.)
I think an irony might be when a person decides he or she stops caring and then discovers a hole in their life. A vacuum. Ya can't let that exist and fester. Humans seem predisposed to care about something. Apathy can lead to narcissism if the will is stronger than the conscience.
more to say, gotta run