Brooke Smith (Erica Hahn) is now credited as a main cast member.

Elizabeth Reaser reprises her role as Ava. Her last appearance was in the third season finale, "Didn't We Almost Have it All?".

Meredith: (voiceover) There’s a reason surgeons learn to wield scalpels. We like to pretend we’re hard, cold scientists. We like to pretend we're fearless. But the truth is we become surgeons because somewhere deep down we think we can cut away that which haunts us. Weakness, frailty, death.

Cristina: What are we looking at?
Izzie: Meredith put her Mom in a baggie and brought her to work.
Meredith: I had to get her out of my closet. She was haunting me.
Alex: Now she’s haunting us all.

Callie: You should direct your questions to Dr. Bailey, Stevens.
Cristina: Oh, we’re directing our questions to Dr. Bailey?
Callie: Oh, not you, just Stevens.
Bailey: Why is Stevens directing her questions to Dr. Bailey?
Callie: Because she’s been sleeping with my husband. Alrighty then, have a good day.
Cristina: (to Meredith) This is more disturbing than your bag full of Mommy.

Derek: What is that?
Meredith: It’s charts.
Derek: Meredith.
Meredith: It’s my mom. I had her in the cubby and she was freaking people out. I was just gonna go put her in the car. Do you think that’s disrespectful? To leave her in the car?
Derek: It’s a little --
Meredith: It’s not that strange. I mean, I’m trying to figure out how to put her to rest. I can’t shove her in the back of my closet anymore. I have to deal with her. And this is me trying ... to evolve. I’m trying here. So, cubby or car?
Derek: You’re asking me if I think you should put your mom’s ashes in your cubby or your car. You don’t think that’s very very strange?
Boy: Are those really your mom’s ashes?
Derek: It’s strange, right? It’s strange.

Mark: You gotta love Halloween. All the crazies come out to play.

Mark: Oh man, you would not believe what just happened to me.
Derek: There is uh, a kid looking for you.
Mark: What?
Boy: Daddy?
Mark: What!?
Derek: Nicely done. (Derek gives him money)
Boy: Thanks.
Mark: I'll be getting you back for that.
Derek: Looking forward to it.

Derek: What did you do?
Mark: I spread the word you were lookin'.
Derek: You spread the word I was looking?
Mark: "Lookin'". It sounds much dirtier without the "g."

Mark: Good morning.
Olivia: Don’t. Don’t do that. Don’t smile at me.
Nurse: Don’t smile at her. Don’t smile at me either.
Olivia: We’re on to you.
Nurse: We’ve compared notes.
Mark: Compared notes? Really?
Olivia: Compared notes. Compared pick-up lines. Compared techniques.
Mark: Techniques?
Olivia and Nurse: Identical.
Mark: Identical?
Olivia: We formed a club. Nurses United Against Mark Sloan.
Mark: Are there any club activities?

Meredith: (voiceover) It isn't just surgeons. I don't know anyone who isn't haunted by something or someone. And whether we try to slice the pain away with a scalpel or shove it in the back of a closet- our efforts usually fail. So the only way we can clear out the cobwebs is to turn a new page or put an old story to rest- finally, finally to rest.

Episode Title: Haunt You Every Day

"Haunt You Every Day" is the title of a song by Weezer.