you become. I celebrated my birthday last week and I find myself being wiser than I ever was 10 years ago. I have also become more private about a lot of things and don't feel like I need to shout on top of mountains every moment of my life if I choose not to. Or that I don't need to break the news right away.
I also definitely have learned that the most important things in life are your health, your family, and your friends. And it's even more about the quality not the quantity of friends either. I also learned that it's no use trying to compete with others and complain what you don't have compare to what they have. There are people out there who also don't have what you have also. There will always be someone out there with more money, more status, more power,etc than you, so no need to worry about this.
I work in a dialysis center with people who have chronic kidney disease. It's a daily reminder for me how grateful I really am to have my health. Sometimes your day goes bad and you can't help wonder why the things happen the way they do. But my line of work puts me back into reality and I am thankful for that.