I'm only in my mid-30's, so don't have too much to give on the advice side but can echo many of the sentiments here. The things that bring me joy, or that I focus on in life...
Never prioritize work over my family/friends. With my wife, two small kids, etc. I have no desire to be a 70 hour/week grinder. It surely means I will earn below my potential but that's okay.
Others have said it... save, save, save. For retirment, for your children's future, etc. Along the same financial lines, sure I could afford a much nicer/larger house. But for what purpose? Instead, live below your means. Spend that money on experiences, trips, etc. rather than another garage stall to put and over priced car in or an extra bedroom that sits empty.
Faith and community. Don't care where you find that. For me it's church, it's mentoring middle schoolers, it's being active in a community and grounded in something bigger than me.
Know what's important. Leaving it generic to avoid certain topics, but too many people's day-to-day lives are entirely dictated by events/circumstances that are out of their control, shouldn't actually dicate whether they are in a good mood or not, etc.