“walk around with those things.”
Elaine: Perhaps there is more to Newman than meets the eye.
Jerry: No, there’s less.
Hello, Newman.
he is merry
Newman: Pair o’ bear claws, please!
I don’t work in the rain.
KRAMER: Oh, right. It’s raining.
George: “Neither rain nor sleet nor sno-- IT’S THE FIRST ONE!”
“And you wanted to be my latex salesman!” 
“I was never that big on creeds.”
Arguably the best line of the entire series. 
“I’m there for you.”
“Three years is a long time to be married.”
“That ‘there for you’ crap was a stroke of pure genius!”
“Oh, no! The Associated Press picked up the NYU story. I’ve been outed! And I was never even in!”
Not that there’s anything wrong with that.
Sometimes it’s not one particular line, but several lines that create the circumstance. The below are just from memory but they approximate the situation:
George: Elaine, I have to tell you something.
Jerry: No, no, don’t do this!
George: I’ve been very attracted to you.
Jerry: Here we go. (Hides head in hands.)
Kramer immediately comes bursting in the door with some trivia, interrupting the proceedings. The only thing Jerry, George, and Elaine are totally in agreement with at this moment is getting Kramer the hell out of there!
There’s a similar scene where Jerry is talking to a woman who acknowledges that she’s a virgin. At that exact moment Elaine comes bursting in. And she’s breathless with a tale about how her purse goes flying into the air and her diaphragm comes flying out!
“We were getting along real good and then she made some tea. Put some milk in it without asking me. Now, that’s a turnoff.”
Mrs. O: That’s when I began my affair with Mohandas.
Elaine: What?
Mrs. O: Mohandas.
Elaine: Ghandhi?
Mrs. O: Oh, the passion. The forbidden pleasure—
Elaine: You had an affair with Ghandhi?
Mrs. O: He used to dip his bald head in oil and rub it all over my body.
“I mentioned the bisque.”
“Hurry up, George, step on it. Damn mohel – he circumcised my finger! … Tissues – I need more tissues!”
“You flinched.”
In that same episode (The Bris) Jerry, Elaine, George, and Kramer visit a hospital numerous times. Kramer becomes obsessed with finding the pig-man (apparently half man, half pig) that he believes he saw on the first visit. Later on, the guys get into a general conversation about pig-men. I don’t remember Elaine’s exact words so I’m somewhat paraphrasing, but it’s something like this:
“OK, I’m getting outta here. But can you do me a favour? When you continue this conversation about pig-men and the women who loved them, can you please tape it? I’ll be fascinated to listen to it when I get back!”
That whole Kramer thing always seemed fantastical to me. I mean, if that guy lived on my floor, I’d have about six locks on my door, and a peephole where I could scan the entire hall. He’d never have the opportunity to slide into my apartment.