Some scenes were improvised, for example, when Jeff advises Arnau to raise his collar and wear sunglasses since they make him look like "a pilot that drives jets".
The original classified ad upon which the film is based first appeared in Backwoods Home Magazine in 1997. It was written as last-minute filler by John Silveira, an employee of the magazine, who is credited in the film as "Time Travel Consultant" and also has a cameo. The ad was later featured on The Tonight Show with Jay Leno (1992) in the "Headlines" segment, and eventually turned into an Internet meme before being developed into a screenplay.
The part of Darius was written for Aubrey Plaza, because writer Derek Connolly wanted to work with her. Jake Johnson was likewise director Colin Trevorrow's first choice for the part of Jeff.
There is an actual Facebook page for Liz McHollis, Jeff's old girlfriend who he looks up while in Ocean View. Anne Sellery and Jennifer Popochock, who were the hair stylists and makeup artists on the film, are her only two "friends." Her hometown is listed as Ocean Shores (which is a real town) and not Ocean View, which doesn't actually exist.
Wesley Schultz: lead singer of The Lumineers (Grammy Nominated band) is in the elevator at the beginning of the film, when Darius is on her way to work.
Derek Connolly: The screenwriter can be seen folding napkins in the background when Darius is interviewed by the restaurant manager.