Jerry: Well, it looks like you've adjusted to the boxers.
Kramer: Well, I wouldn't go as far as that.
Jerry: You went back to the Jockeys?
Kramer: Wrong again.
Jerry: Oh no...
Elaine: What? What?
Jerry: Don't you see what's going on here? No boxers, no Jockeys.
Elaine: [move back away from Kramer.] Ohhh.
Jerry: The only thing between him and us is a thin layer of gabardine. Kramer, say it isn't so.
Kramer: Oh, it be so. I'm out there, Jerry, and I'm loving every minute of it.
The Gymnast - S6-E6
Jerry: So let me get this straight. You find yourself in the kitchen. You see an eclair, in the receptacle, and you think to yourself...what the hell? I'll just eat some trash.
George: No, no, no, no, no. It was not trash.
Jerry: Was it in the trash?
George: Yes.
Jerry: Then it was trash.
George: But it wasn't down in, it was sorta...on top.
Jerry: But it was in the cylinder.
George: Above the rim.
Jerry: Adjacent to refuse is refuse.
George: It was on a magazine, and it still had the doily on.
Jerry: Was it eaten?
George: One little bite.
Jerry: Well, that's garbage.
George: But I know who took the bite. It was her aunt.
Jerry: Well, you my friend, have crossed the line that divides man and bum. You are now a bum.
The Switch - S6-E11
Jerry Seinfeld: Don't you know what it means to become an orgy guy? It changes everything. I have to dress different. I have to act different. I'd have to grow a mustache and get all kinds of robes and lotions and...I'd need a new bedspread, new curtains. I'd have to get thick carpeting and weirdo lighting. Of course, I'd have to get new friends. I'd have to get orgy friends. No. I'm not ready for it.
The Switch - S6-E11
George Costanza: Do you ever just get down on your knees and thank God that you know me and have access to my dementia?
The Gymnast - S6-E6
Mr. Pitt: I have been accused of wrongdoing, but these false accusations will not deter us. We will annex Poland by the spring at any cost! And, our stocks will rise high!
Chosen answer: George does mention his brother in the episode "The Parking Space". They actually really never mention anything that contradicts the fact he had a brother though, it just isn't mentioned.