To me, it means a general sense of shame.
I'm glad I live in a place of general abundance and I have everything I need and some of what I want, but being someone who reads extensively, I keep finding myself learning things that were deliberately withheld from me in the public school curriculum and I understand why the rest of the world hates us. (Some examples, the Tulsa Massacre, the Battle of Blair Mountain, railway strikes in the 1800's, etc.)
I don't stand up for the national anthem either, because even though I was born here, this country doesn't represent the values important to me. (living wages, health care, leaving people the fuck alone even if they're a different religion, etc.)
It's punctuated every election season, when I watch 49% of Americans make excuses for genocide, poverty, and endless war while the other 49% pretends to give a shit just because the other team's guy is currently in charge. There's never any meaningful self-reflection by either 49% in the wake of massive negative change.