It makes you wonder what went on that weekend. Other examples?
“If you could see what I’ve seen with your eyes.”
Partially described in the Tears in Rain soliloquy
“If it weren’t for my horse, I wouldn’t have spent that year in college.”
from anonymous person as shared by Lewis Black
My grandparents always told me “Don’t go into Huallaqui Canyon!” But they would never say what it was they had done in there.
Overheard remarks:
“Of course, after that he wasn’t much use to her. Well, not as a husband.”
Hemingway once wrote a short story in six words:
“For sale: baby’s shoes, never worn.”
Yeah, that’s the classic one that came to mind. It’s often attributed to him, but there’s no evidence for it. (A bit on it here and here.)
“Snakes. Why did it have to be snakes?”
Similarly, a one-liner that suggests a great story (that we know):
Elsa: What’s this?
Indiana Jones: Ark of the Covenant.
Elsa: Are you sure?
Indiana Jones: Pretty sure.
“She’s so fine, there’s no telling where the money went.”
- Robert Palmer, Simply Irresistible
For Hemingway, I will offer an exchange from The Sun Also Rises:
“How did you go bankrupt?” “First gradually, then suddenly.”
“You and I remember Budapest very differently.”
Nazis. I hate these guys.
Yes, alcohol was a factor.
Maybe not a great story, but probably interesting.
This one time, at band camp…
We thought about it for a long time, “Endeavor to persevere.” And when we had thought about it long enough, we declared war on the Union.
I’ve got debts that no honest man can pay.
The sky above the port was the color of television, tuned to a dead channel.
Some people use the smell of burnt flesh as their benchmark of horror, but I didn’t think it was so bad.
I slept with three generations of that family.
“My own brother, Aberforth, was prosecuted for practicing inappropriate charms on a goat.”
These are the voyages of the Starship Enterprise.
It’s bigger on the inside!
The dog did nothing in the night-time … that was the curious incident.
(I know that last one is actually two people talking, but it’s a classic! 
)
Goddamn you! This was going to be my contribution.
There’s a trope about that. Because of course there is.