Last night’s Grey’s Anatomy changed the series for good. As we close one chapter, let’s take one last look before we turn the page in the series.

Spoilers ahead for Grey’s Anatomy season 11, episode 21, “How to Save a Life.”

George O’Malley, Mark Sloan, Lexie Grey, and now another doctor hangs his scrub cap for the last time in Seattle: Derek Shepherd. Last night’s Grey’s Anatomy saw Derek Shepherd doing what he does best, saving lives and teaching others to do the same. Even though the latter action only panned out inside his head, Derek spent his last moments encouraging fellow surgeons to persevere and be their best.

ICYMI: Grey’s Anatomy: 10 years, 10 memorable deaths

While we believed that a season 12 contract with Patrick Dempsey’s signature on it was a done-deal, nothing is predictable on Grey’s Anatomy.

Related: Grey’s Anatomy season 11, episode 21 recap: Everything ends

Before Grey’s Anatomy returns next week with a two-hour farewell for Dr. Shepherd’s fellow surgeons to say goodbye, we look back at our favorite lessons Dr. Shepherd taught us over his 11 years in the OR and on our screens.

1. Adding “Mc” to something makes a person far more attractive

What is it about adding a prefix to an adjective that turns a dreamy man into McDreamy? While the science behind this is not exactly getting funding for further research, Grey’s Anatomy taught us with the simple addition of two letters, doctors can go from sleazy to McSteamy.

2. No matter how perfect your partner is, you still need a person

If you find a person you are lucky enough to love for life, that is great. But that person may not be your “person.” As Derek proved time and time again, making room for another “person” in the relationship is not only healthy, but a way to make sure that you only have to deal with half of the gossip you don’t care to hear.

3. It’s always a beautiful day to save lives

Storming, flooding, patients dying in mass numbers, regardless of what you are up against, you must focus on one thing that is in your control. For Derek it is the body on the table in front of him in that moment. As everything else outside the OR falls away, suddenly the day does seem a little brighter and easier to handle.

4. Do what you have to do

Sometimes the choices are tough, say leaving your wife for another woman. Other times it is as easy as putting on a crown and sipping tea with your daughter. Derek never backed away from something because it was beneath him or too hard.

5. Swallow your pride

Okay, it took Derek a long and winding road to figure this one out, but eventually he got the memo. Clipping the bleeders and having the opportunity to do what others cannot can be enough for one person. After trying and failing to get behind Amelia’s leadership in the hospital, Derek eventually came around and decided that two Shepherds at the top of their field is better than one ego-maniac.

On the next page: Friendship, love, and happy endings

6. Love in friendships is endless

This one hurts a bit if you imagine Mark and Derek hanging out on the porch of that big trailer out in the open fields of the sky. Even after Mark slept with his wife, drove Derek out of town, reappeared in his life, and again slept with his wife, Derek and Mark remained close friends. They fought, they reconciled, they grieved, they supported each other through it all.

7. Fight for those you love

Derek fought for Meredith from the moment he woke up on her floor in the series premiere of Grey’s Anatomy. Most of the time he was fighting only Meredith for her love, but sometimes, he found himself defending her honor, intelligence and worth to those who could not see it. Even in death, Derek referenced Meredith’s surgical skills in his head, arguing her intelligence over the doctors operating on him.

8. Go big or go home

Map out your future home in candles? Check. Propose in an elevator where some of your most romantic moments happened and fill the walls with surgeries you worked on together? Check. Get married on a post-it because you know that’s how it should be? Check. Derek set the bar high for any romantic gesture, but he also knew when to tone it down and keep it simple to ground you in the moment for as long as possible.

9. We are all entitled to have our things

Ferry boats appeal to Derek almost as much as fixing brains do. From his scrub caps to his commute, Derek’s love for ferry boats was with him even in his final day as he rode one his last morning in Seattle. Even after the crash of the commuter ferry, Derek’s love did not waiver.

10. The story isn’t about the happy ending, but the pages in between

Their story was never easy. It was messy, it was emotionally scarring, and it ended. Meredith Grey was the girl at the bar. Derek was the guy across the bar. In the end, she was the wife and mother leaving home to save lives and he was the husband who always found his way back until he couldn’t fight for himself anymore. It is a love story that will stand in television history as one of the greats, but it is over.

Goodbye, McDreamy. We’ll miss that smile most of all.

Say goodbye to Derek in Grey’s Anatomy season 11, episode 22, “She’s Leaving Home,” Thursday, April 30 at 8:00 p.m. ET on ABC.