Seems to me that depression is almost a culturally acceptable expression of the saying "misery loves company." From childhood, we're taught that it's socially acceptable (and might even garner sympathy and attention) when we complain about things and feel bummed out about them. That's a very different underlying dynamic from celebrating what is good... in fact, when we celebrate what is good, we often get negatively labeled as "naive" or even a "Pollyanna." So that sets up a cultural dynamic in which we're more encouraged to socially share negatively than positively.

Just look at the microcosm of Steemit. People who complain endlessly about not making money on their posts are "supported" with lots of "me toos" and further moping about the system. If someone celebrates that they made $100 on their post... "they probably cheated" or it was "only because they have friends who are whales."

So that's the additional backdrop for what you're sharing here... no wonder depression is so much more prevalent than happiness.