Two Lines
One is irritating, and the other is funny.
First, the irritating one. Is anyone else annoyed when after the grandmother's heart incident Phil says to his son, "If she's careful she might be fine until you're grown up and married and have kids"? The assumption that OF COURSE Tommy WILL marry and have children really irritates me.
Second, I always laugh when Kathy and Phil are in Kathy's apartment after Anne's party, disussing Phil's assignment. Kathy wants to tell her sister that Phil isn't really Jewish. After all, she reasons, "your mother knows." And Phil answers, "Yes dear, she had to."
Yeah, well, naturally Phil's MOTHER doesn't think her son is Jewish!
Edited to add: Three lines, actually. There's a bit of dialogue near the start of the film that I think is both funny and telling. Phil is struggling to explain to Tommy what Jews are, specifically how someone can be a Jew AND an American. He talks about the fact that there are different countries:
Phil: The language is different and the food is different and the flag is different --
Tommy: And the airplanes are marked different...
Phil: Differently, yes.
Being a writer, Phil is fine at correcting his son's grammar; explaining to him all the implications of being Jewish is a much more difficult task!