The people on the bottom half of the 'K-shaped recovery' outnumber the people on the top half. This bias likely skews the Michigan Consumer Sentiment survey [1], and accordingly leads to record low optimism about the future, despite historically low unemployment.

Add to that, the rapid expansion of automation -- both in white collar and blue collar settings -- and it isn't hard to see why few can take solace in an extended recovery and expansion.

[1] https://www.sca.isr.umich.edu/files/chicsh.pdf

You can see the business cycle each time there's a giant spike in the amount of debt carried by institutions that isn't paid down before the next one.