I've always been pretty introverted, and also a night person. I used to roll into work around 10:30 or so, after a long chill morning.
When I got married and had kids, that schedule wasn't feasible any more. For a couple of years, I would set my alarm as late as I could get by with and then rush rush rush in the mornings to get my daughter ready and at day care and myself ready for work. That way, I could still be as much of a night person as I used to be.
It was a disaster. I felt tense and unbalanced all day. Lots of fights with my wife. By the time the evening rolled around and the kid was in bed, I had a little free time, but I was too spent to do anything useful with it.
At some point, due to commute changes, I ended up getting up at 6:00 to avoid the worst of rush hour. That was even worse. There's nothing quite like getting up early to stare at brake lights ahead of you for 45 minutes every morning to make you lose the will to live.
When my commute fortunately got much better—a five minute drive—I decided to try keeping my 6am wake up time.
Holy crap, it was amazing.
I had a solid two hours before the wife or kids woke up. The house was silent and all mine. I could have a quiet cup of coffee, read a bit, work on projects.
What I figured out is that, while I like being around people, my personality or sense of self kind of deflates during it. I don't have enough courage or force of will to be me in the presence of other people. Their own circles of identity sort of press into mine, and I'm not confident enough to easily push back all day.
That solitary time in the morning is exactly what I need to reinflate my bubble. To sort of gather around myself a sense of who I am, and what it is about myself that I like and feel good about. When I have that time in the morning, I can go out into the day feeling a little more secure and insulated. Without it, I feel exposed.
It's so worth becoming a morning person to get that feeling.
(Alas, now my kids have to be at school earlier, so they are getting up shortly after me and I don't have much quiet time anymore. I'm tempted to try getting up even earlier, but getting up at five is really hard.)