The blue pillars in the restaurant are actually reused props from "The Melty Man Cometh". They were originally the two pillars that were at the foot of Patrick's bed.
(Steve answers his mobile)
Steve: Jeff. I know that was my idea, but that was absolutely the worst timing in the history of everything ever! (No one answers) Jeff? Hello? (He pauses, then he realizes who it is) Jane? Is that you? (No one answers.) Jane, if that's you, could you once and for all just get over it? Look, Susan is the one I'm going to marry... (No one answers) Jane?
(Steve turns around, and sees Susan standing there)
Susan: In every possible sense of the word... (She holds up her mobile) Gothcha!
(Susan is moving her foot, under the table, into Steve's groin)
Steve: You know, if this is some kind of revenge thing, I think I'm kind of okay with it.
Susan: Oh this isn't the revenge part, this is... (To a waitress) Excuse me?
(The Waitress walks over)
Susan: Could you tell us the specials please?
Waitress: Of course, yes. We've got Duck, with an orange...
Steve: (groans in excitement, than pauses, to look up at the waitress) I really like duck.
Waitress: And, uh... we have steak...
Steve: Woooooooo! (pauses) Steak, eh? Steak, steak, steak!
Susan: (To the waitress) Wait 'till you get to the sweets. He'll blow his top, promise you.
Patrick: I'm sorry Steve, but you've been with Susan a year now. Either you think you have a future or just get married.
Jeff: Steve, you know what the sentence of death is, don't you? I don't mean the sentence like in executions and stuff, I mean the scary one... Just five words, Steve. Five little words. 'Where. Is. This. Relationship. Going.
Jane: I really quite like being single. Except for the bit about not having a man.
Steven Moffat has said there was a major rewrite done to Sally and Jane's storyline because it fell flat during rehearsal.
A nice bit of continuity: Susan mentions May 12th as being Steve and Susan's anniversary. The pilot episode of the series aired on that date.
Noakes, the last name of the groom whose wedding the group is going to, may possibly be named after Unit Publicist Anna Noakes.
Sally, Jane, and Susan: We're going to be Woodies.
The three girls talk about Buzzes and Woodies, the characters in the movie Toy Story, about how Buzzes flew off the shelves, but the Woody toy was left on the shelf. They compare it to Susan and other girls who get married quickly, and how Sally and Jane will be left single.