1. Not traveling when you had the chance.

Traveling becomes infinitely harder the older you get, especially if you have a family and need to pay the way for three-plus people instead of just yourself.

2. Not learning another language.

You'll kick yourself when you realize you took three years of language in high school and remember none of it.

3. Staying in a bad relationship.

No one who ever gets out of a bad relationship looks back without wishing they made the move sooner.

4. Not quitting a terrible job.

Look, you gotta pay the bills. But if you don't make a plan to improve your situation, you might wake up one day having spent 40 years in hell.

5. Not trying harder in school.

It's not just that your grades play a role in determining where you end up in life. Eventually you'll realize how neat it was to get to spend all day learning, and wish you'd paid more attention.

6. Not realizing how beautiful you were.

Too many of us spend our youth unhappy with the way we look, but the reality is, that's when we're our most beautiful.

7. Failing to finish what you start.

I had big dreams of becoming a nurse. I even signed up for the classes, but then…

8. Caring too much about what other people think.

In 20 years you won't give a damn about any of those people you once worried so much about.

9. Worrying too much.

As Tom Petty sang, Most things I worry about never happen anyway.

10. Not being grateful sooner.

It can be hard to see in the beginning, but eventually it becomes clear that every moment on this earth -- from the mundane to the amazing -- is a gift that we're all so incredibly lucky to share.