I don't have time right now, but suffice it to say that at the end of the day, I'm in the same boat as you. Economies grind on, and US companies are exposed to the vagaries of not only the US markets, but also overseas markets, and demographic shifts. I worry about such things, and don't have faith that markets will keep grinding higher. There are alternatives, and there must be found a way to keep injecting money into the system.
These things are not rational. I heard the other day that the best-performing asset over the past 10 years, or maybe 20 I can't remember, is gold--yet still nobody likes it. I admit that I have a position, but that it is small, and always has been. I like it, and even I don't pursue it more strongly.
I still try to beat the markets with my overall portfolio, and have been lucky enough to do so (the important thing is LUCKY with the particular assets that I own). Those years my equities have beaten the S&P have mostly been years where the S&P has performed poorly, but this could be one of the few years where I beat it after it has done well.
Point being that I believe that sentiment drives flows which drive markets. Even though I try to invest (gamble) accordingly, I still make seemingly weird plays, like while knowing that China and others are dumping US debt, I still have a bunch of it. My personal sentiments are only sometimes aligned with the aggregate.
What I have learned is to buy low, and not sell low. THIS is the critical element that people miss. For a few years I momentum traded, which went very well but required a lot of work, in hindsight not enough to justify the alpha. Buying something that has been beaten up is tough for most to do, therefore they DCA into things like VOO. It is STILL tough for me to do, but I suck it up and do it because I know that it will be good for me, yet I still feel that it's bad.
I was well up yesterday, and am again today, so far, with my tobacco portfolio. Everyone said to stay away, because governments were killing it, and because they carry "too much debt". Many of the majors--BTI, MO, PM, etc. Doing great. I have also learned to not be wedded to anything other than my wife. I would dump them in a second. Sentiment would dictate that I sell.
Maybe I should buy some miners! lol I am not that much of a contrarian.
In a year that was projected by many to be "nothing", to be "tough going", I have so far had the 3rd best equity gains ever in my portfolio, but the year is far from over. Thankfully I am stabilized out a ways, so the biggest thing I worry about now is taxes going forward.