The fictional band "Munchausen By Proxy" featured in the film is named after the Münchausen syndrome by proxy, which is a psychological disorder, and is composed of actress/singer/songwriter Zooey Deschanel and the real-life band "Von Iva", which got the part after music supervisor Jonathan Karp saw the cover of their CD in Amoeba, in Hollywood. On Lakeshore Records' soundtrack release they are credited as "Munchausen by Proxy (f/ Zooey Deschanel & Von Iva)".
Based on an autobiographical book written by Danny Wallace, a British author, producer, and journalist who spent a year answering "yes" to any given question or proposal and recording the results.
Before Lucy's bridal shower, Carl is checking his messages and listens to one from Rooney explaining he got into a car accident and his car's front bumper is missing. Later after Carl is leaving Stephanie's apartment, his car has it's front bumper.
When Carl is in the hospital and realizes how to reconcile with Allison, he asks the time, and is told "5:40 AM." However, we can clearly see strong daylight illuminating the closed blinds of his hospital room. Then, when he runs outside of the hospital, it is midday. When he arrives at Griffith Observatory, the lighting changes back and forth from midday to early morning.
Allison: Have you met my friend Ian? He's a computer hacker. He helped me erase your MySpace page, and your band's MySpace page, and your FaceBook page. Happy networking, asshole!
Allison: [singing with her band]
Don't call me past 11pm, it won't happen again. Happened once, it happened twice, it happened three times, maybe four times, maybe five times, maybe, maybe it happened six times, but it won't happen seven times.
Allison: [singing with her band]
Don't call me past 11 PM, it won't happen again. You can call me at 10:59 but don't call me at 11 because that's my rule now.
The following FAQ entries may contain spoilers. Only the biggest ones (if any) will be covered with spoiler tags. Spoiler tags are used sparingly in order to make the page more readable.
Q
Is this movie based on a book?
A
Yes. The film is based on the 2005 biography Yes Man by British humorist Danny Wallace. Wallace describes the six month period during which he said "yes" to everything that was offered to him and how it affected his life.
Q
How does the movie end?
A
Carl's ex-wife Stephanie wants to sleep with him again, but he says "No". As he leaves, bad things begin to happen to Carl (his elevator stalls, his car is towed). Carl hides out in the car of Terrence, the person who started the "Yes" program to remove the "Yes Covenant" from him. This leads to a car accident and Terrence telling Carl that he doesn't always have to say "Yes" if he doesn't want to. Carl then goes and meets Allison at her jogging class and he eventually convinces her that they should be together. The final scene shows Carl and Allison donating a truck full of clothes to a local shelter. When asked where he got the clothes, the scene switches to Terrence's latest "Yes!" seminar, where everyone is naked, implying that Carl asked them all to donate their clothes, to which they apparently responded, "Yes!"