One Tree Hill is a show that just sticks with you. No matter when you watched it last or how many times you've watched it, Nathan and Haley still have the perfect relationship and Brooke Davis is still a badass. OTH never goes out of style and the lessons it teaches viewers will always be relevant.

1. You aren't defined by who you were yesterday, let alone who you were in high school.

We meet Brooke Davis in episode 2 and she's a boy-crazy party girl. We see her stumbling around at parties, getting into trouble, and not caring about her future. Brooke's transformation is inspiring and powerful. She becomes class president, starts her own business in high school, and becomes a successful woman who builds relationships with her classmates and parents. By the end of the series, Brooke Davis is the woman we aspire to be.

2. Age doesn't determine your ability to love.

Nathan and Haley's love story starts out as a typical jock-nerd love story where the jock is just using the nerd and ends up falling in love with the nerd. Yet, it's so much more than that. They defy the odds and make their marriage work. Most of the world couldn't get married at 16 and have a baby on the day of their high school graduation and still have a functioning, healthy, loving relationship. They're a stable relationship that we can all strive to have one day.

3. Bad things happen and there's not always an explanation for them.

The school shooting episode is one of the most heartbreaking episodes of OTH. Jimmy Edwards bringing a gun to school was sad enough, and then we watched Dan Scott shoot Keith Scott in cold blood. Keith had tried to be the best brother to Dan that he could be and always tried to see the best in him. And Dan repaid him by shooting him because he was jealous of him.

4. Family matters.

Nathan and Lucas start the series not acknowledging each other, let alone being brothers. Lucas and Keith stick to their side of the town and Dan and Nathan stick to their side. They didn't know each other and had nothing but hatred for each other. We watch Nathan mature and Lucas stop blaming Nathan for what happened to his mom. They build a relationship that forces Dan to talk to Keith more. While the relationships weren't easy by any means, it showed us the importance of family because you don't know how much time you'll have with them.

5. Time will pass regardless, it's up to you to make it count.

Nathan says it best in the series finale and brought us all to tears.

The life lessons that OTH taught us will stick with us no matter when the last time we went and visited Tree Hill.