Just how much do we change?

I was recently inducted into the halls of Facebook. Rather: after a year of harassment from one friend, I decided to open a profile so she would stop. My facebook page lay dormant for about a month, and I was wondering what all the fuss was about, until it started. The avalanche. First one long-lost friend found me, and then they kept coming, at about one friend a day. I'm now addicted, it's the modern equivalent of "This is YOUR LIFE!", a TV show that I never saw but that Sesame Street spoofed (and we had Sesame Street in Hong Kong), so I feel like I know what the show was about.
So I now spend about a half an hour a day cruising through the profiles, photos and posts of these people I haven't seen nor heard from in 20 years, and searching for more on the site, and now, yes, harassing my friends into joining. I get it.
And what I gathered from all this so far is that we don't change all that much. Sure, the faces have matured some, mostly the faces seem longer somehow. But it seems the personalities have changed little. The brash and obnoxious people of my youth (one friend called them "the boneheads") pose grinning with their hairy chests exposed through half-buttoned shirts. The sweet and unassuming ones of yore send little notes asking for news and offering congrats and encouragement.
As I was thinking about that, I was shocked by the thought that perhaps I hadn't changed all that much either. WHAT? I did therapy, I moved far far away, I worked hard to change. But now that I've sat with this thought for over an hour, I can see that perhaps I am unchanged, in some fundamental ways. I sit back on popularity contests. I smirk at overconfidence. I brood deep dark thoughts. The biggest change is that back then, I was fundamentally unhappy. I'd have to report, happily, that I am now fundamentally happy. That's a biggie.
Well of course now I can project wildly onto my mostly-unformed daughters (or are they?) This past month, I have felt madly in love with my girls; both of them are in a happy, confident phase right now, and parenting hasn't been too challenging. They are eye-candy to me. But I can see some fundamental traits of their personalities unfolding. Chloe is not a joiner. She does not enjoy the spotlight, tucking her chin to her chest and pouting. In preschool, her teachers aren't too pleased with this, but hopefully next year she joins a Montessori language-immersion program in which that personality is an asset. Her speech is developing so fast that she is fascinated by it, and isn't too interested in sitting still for hands-on activities, she wants words and lots of them. What's going to last, and what's a phase? Sophie is a joiner in every way, she wants to be in the thick of a crowd, touching and seeing what everyone else is. She laughs when others do. She is pleased with attention, rolling onto her back to bask in it.