With time and experience, life teaches us all lessons. I keep a running list of my “Secrets of Adulthood” — the things I’ve learned, the hard way. (For instance, here are my Secrets of Adulthood for Habits.)

I write about these in my books, I talk about them in my podcast “Happier,”

I think about them all the time. There’s something about distilling an idea or observation into a proper “Secret of Adulthood” that makes it easier for me to remember.

1. What I do every day matters more than what I do once in a while.
2. For the most part, I’m very much like other people, but our differences are very important.
3. Hell is other people; Heaven is other people.
4. Every medicine can become poison. (Email, caffeine, social media, work, treats…)
5. I manage what I monitor. So if something’s important to me, I should figure out a way to monitor it.
6. Never let myself get too hungry, too sleepy, or too cold. And never pass up the chance to use a bathroom.
7. I bring my own weather to the picnic.
8. Just because something is important to me doesn’t mean that it’s important to someone else.
9. A stumble may prevent a fall. This relates to the Strategy of Safeguards in my book Better Than Before.
10. One of the best ways to make myself happy is to make other people happy; one of the best ways to make other people happy is to be happy myself. This is one of my Eight Splendid Truths of Happiness.
11. Outer order contributes to inner calm. I’m finishing up a little book with this title. Stay tuned.
12. I can’t expect to be motivated by motivation. This realization was a big inspiration for my forthcoming book The Four Tendencies.
13. It’s easier to change my circumstances than to change myself.
14. Things often get harder before they get easier.
15. The things that go wrong often make the best memories. My mother told me this, to calm me down before my wedding weekend.
16. Choose the bigger life.
17. Turning a computer on and off often fixes a glitch.
18. When I give more to myself, I can ask more from myself. This relates to the fun and helpful Strategy of Treats.
19. What’s fun for other people might not be fun for me–and vice versa.
20. Don’t let the perfect be the enemy of the good. Cribbed from Voltaire.
21. Now is now. I write about this in the conclusion of my book Happier at Home — which, I must say, is one of the best things I’ve written in my whole life.
22. If I need to remember something, write it down. How many times have I regretted remembering this Secret of Adulthood?
23. Working is one of the most dangerous forms of procrastination.
24. There is no wizard. (I will explain this in an upcoming episode of “A Little Happier.”)
25. The days are long, but the years are short.

What are your Secrets of Adulthood? I’d love to add many more to my list!

Gretchen Rubin is the author of the #1 New York Times Bestseller The Happiness Project—an account of the year she spent test-driving the wisdom of the ages, current scientific studies, and lessons from popular culture about how to be happier—and the recently released Happier at Home and Better Than Before. On her popular blog, The Happiness Project, she reports on her daily adventures in the pursuit of happiness. For more doses of happiness and other happenings, follow Gretchen on Facebook and Twitter.

Image courtesy of Darius Bashar.