The biggest difference is fewer "friends" (were they, though, really?) and fewer in-person interaction.
Having developed chronic illness, a lot of the day-to-day physical calculus has changed.
My perception of myself hasn't changed much, but my perception of others has, drastically. The desire to fit in and maintain position in social hierarchy even unto death is far more prevalent than I ever could have imagined. But I've also found a camaraderie that I never could have hoped for or expected.
Virtually everyone from TheBeforeTimes™ has drifted away.
Life is still full of roughly the same number of good days and bad. The structure of our civilization is much more resilient (for better or, mostly, worse) than I would have believed.