When you date someone it's like you're taking a class in them and when you break up it's like all that knowledge is useless. It's the emotional equivalent of an English degree

Ted: Pop quiz. When robin is PMSing what kind of chocolate should youg et her?
Barney: Trick question. Get her butter scotch.
Ted: Correct. Why?
Barney: Butter scotch is to Canadian women what chocolate is to American women

If you ever see this face, whatever you do, run and do not take a picture or she will punch you.. and you will cry.. for the third time... that night

Ted: You were like the worst student in the world, weren't you?
Barney: They said I AD...something... can we have class outside?

Don't cry in front of her, and whatever you do, don't cry in front of her four times

Jen: We're going to die alone aren't we?
Ted: Well, you'll have your cats

Ted [about Barney and Robin]: You do realize that they were lying to you
Lily: No, they don't realize that they weren't lying

Barney: How do you keep a girl from becoming your girlfriend? Simple, the rules for girls are the same as gremlins. Rule number one: never get them wet. In otherwards, don't let her take a shower in your place. Rule number two: keep them away from sunlight. i.e don't ever see them during the day. And rule number three: never feed them after midnight. Meaning she doesn't sleep over and you don't have breakfast with her, ever
Ted: What about brunch? Is brunch cool?
Barney: No Ted, brunch is not cool

Ted: Okay, I'm going to say something out loud that I've been doing a pretty good job of not saying out loud lately. What you and Tony have, what I thought for a second you and I had, what I know that Marshall and Lily have, I want that. I do. I keep waiting for it to happen. I'm waiting for it to happen. I guess I'm just tired of waiting. And that is all I'm going to say on that subject.
Stella: I know that you're tired of waiting. And you might have to wait a little while more but, she's on her way, Ted. And she's getting here as fast as she can.

Robin: When PJ had a job, he was sexy. He was guardian of the bathroom key. A hot guy telling you when you can and can't pee? That's the dream.
Ted: That's the dream? That's the dream?!?!?! Like what Martin Luther King was talking about??

Ted: What is an ETR?
Barney: It's an Employee Transition Room.
Ted: What does that mean?
Barney: Well, it's a space where a supervisor and an employee engage in a knowledge transfer about an impending vocational paradigm shift.
Marshal: People get fired here

Marshall: Ted, Karen's a douche.
Ted: Wow, thanks for sugar-coating it.
Marshall: "Douche" is sugar-coating it