How I wished it would end (spoilers)
Sometimes you get tired of twists but...how awesome would it have been if at the end when the boat comes back in town there is only 1 girl.
The movie lacked surprise and it was ho hum.
What if for scenario 1 it is Lake Bell's character and she kills the other because she never liked the other girl anyways, have the annoying voice over while it shows a brief montage of her with the other's man, her talking about how maybe she got some accolade in high school she had wanted but the other got, etc. and she kills her
or Scenario 2 it is Kate Aselton's character and she kills the other because of the sleeping with her man
With either scenario she pins it on the men having done it.
You're So Cool