I was put in charge of the T.A.H.I.T.I. project so those people are my responsibility. If going back in this machine saves even one life, then it's worth the risk.

Coulson

Fitz: He'll recover, he did before. Besides brains never delete files they just lose connections, but there's always a back up. It's just a matter of digging and finding them.
Mack: So you've got back up files too?

Simmons: She had GH.325 in her blood.
Coulson: A T.A.H.I.T.I. patient?
Simmons: Whoever killed her also had GH.325 in their blood.

Skye: You two don't have a single thing in common unless you have some Enya albums you've been hiding.
Coulson: No, nothing in common at all.
Skye: I take that back.

May gave specific instructions, you go on a date with a crazy wall I have to chaperone.

Skye

Mack: Look I know you two have a past but from what I've seen the only thing that makes him worse is you.
Simmons: I know, why do you think I left?

Senator Ward: The American people are looking for a simple enemy Mr. Coulson. It's what makes them feel safe.
Coulson: And how do you think they'd feel if they knew your brother was HYDRA? That's an awfully complicated idea to grasp. Especially in an election year.
Senator Ward: Are you threatening me Mr. Coulson?
Coulson: No, I'm telling you I have your brother in my basement.

She can handle it. Deception's her forte. I mean that sincerely, not passive-aggressively. As in it's a good attribute for a spy.

Hunter

Guess being a douchebag runs in the family.

Skye

Coulson: I don't know how else to explain it but it needs to be carved.
Skye: Does it just appear in your mind like some sort of vision?
Coulson: No, it just kinda happens. Which is really frustrating because no matter how much I carve it still means nothing to me. I don't even have a theory.
Skye: I do. It's a map.

Skye: Hold on are you saying that I am an alien?
Coulson: It's a theory.
Skye: No a theory is what scientists use to prove things in nature. This is you telling me that I might be an alien. That is not something you just say like it's no big deal.
Coulson: I was trying not to rattle you.
Skye: Guess what? Epic fail.

To be honest I was almost relieved when SHIELD put him down. The Garrett I knew was long gone since the writing started. And whatever took his place, I don't think it was meant to survive.

Ward

Agents of S.H.I.E.L.D. Quotes

The world is full of evil, lies, pain, and death and you can’t hide from it. You can only face it. The question is when you do, how do you respond, who do you become?

Coulson

Hill: Then New York was invaded by aliens, and they were beaten back by among others, a giant green monster, a costumed hero from the 40s, and a god.
Ward: I don't think Thor is technically a god
Hill: You haven't been near his arms.