My impression of all sorts of people is that they have lots of pleasure on a daily minute-to-minute level from lots of sources. (Not every minute, but often enough to consider themselves happy if you ask them superficially when they're in a good mood.) However, the emphasis on existential happiness is spot-on. Most people don't even think about existential happiness, but you can measure it in what they do. I think the bad choices people make over and over (the first teen pregnancy, then the second one, not arriving to work on time when they most need the job) is evidence that they feel fatalistically unhappy and at some level are passive-aggressively sabatoging what is at core a crappy life. This latter bit is from U.S. culture. I don't remember what it was like in Europe at the moment (though I might hypothesize that a certain cultural cynicism is actually protective and comforting) and I think some Eastern Europeans I've met have a culture that existential happiness is unobtainable or meaningless and they are strong for that and I fail to interpret what seemed like ennui or indifference in some African families I spent time with.
Personally, I'm highly motivated and I think I make 'carpe-diem-type' decisions. Yet when I get too enthusiastic about something, I do (deliberately) temper that down with reminders that I'll be 'old' in a subjectively short period of time; it's not like I'll live forever. I do this because I don't want it to be such a rude shock as things start changing over the decades. In other words, even though I relatively have a lot of subjective freedom, I feel existential angst too.
That's interesting about not letting yourself feel too happy. Is preventing a rude shock which may not happen (you could die suddenly or anti-aging tech could be developed) worth putting the brakes on feeling happy?
I've realized that one reason [1] I don't reliably allow coordinated joint mobility in T'ai Chi is that it doesn't feel natural/allowable for me to feel that good. I'm not sure what's behind that.
[1] The other reason is that it takes a lot of mental focus to change movement habits.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: