Director Evan Goldberg created a game for himself during filming. The goal of the game was to get as many cast members as possible to say, "No, I can't do that," or get them to refuse to do something. According to Goldberg, the only people he was not able to break were James Franco and Seth Rogen.
Initially, Michael Cera was not actually slapping Rihanna's butt, but rather making the motion and stopping right before touching her. As a result of the enclosed space forcing awkward camera angles, the scene was not working on camera because it looked too fake. Eventually, Cera asked Rihanna if he could actually slap her butt. She said yes, but on the condition that she be allowed to really smack him across the face each time. Cera agreed, but Rihanna neglected to mention, much to Cera's chagrin, she would be slapping Cera harder with each take.
The day Seth Rogen filmed the first scene of the movie, where he goes to pick up Jay Baruchel at the airport, is also the same day he filmed a special feature for the movie Paul (2011). Rogen never bothered to change his wardrobe, and is wearing the same clothes in both movies.
According to Seth Rogen, Danny McBride was the person who made everyone laugh and break character the most. At one point, it took eighteen takes, and over an hour for the cast to get a joke on film, because McBride's delivery kept making everyone laugh.
Seth Rogen said that he was shocked by how much the actors would insult each other. According to him, Jonah Hill and James Franco, in particular, seemed to go at each other the hardest. At one point, he felt like he had to intervene and remind them that they are actually friends, and like each other.
In an interview with the Rod Ryan Show on Houston radio station 94.5 The Buzz, Craig Robinson revealed that Jonah Hill improvised asking for a bite of the Milky Way. The other actors improvised the following conversation regarding who gets to eat the Milky Way.
The bright, colorful windbreaker that Michael Cera wears in the movie was his idea. According to Seth Rogen, this was the only condition Cera had before agreeing to be in the movie. This shocked Rogen, who thought that he would complain, or be unsure about the inappropriate behavior that was in the script.
Seth Rogen and Evan Goldberg made the decision, early on in the process, to not include any significant others or family that the actors have. They felt that if they had to deal with this aspect, the movie would get too dark. For example, Danny McBride was a newlywed and had a new baby, but there was no mention of this, and Rogen's soon-to-be wife, Lauren Miller, was not shown during the scene where Rogen and Jay Baruchel enjoy their afternoon of video games and smoking pot. James Franco suggested having his brother, Dave Franco, (who is friends with the group, and is also an actor) in the early party scene, but Rogen rejected the idea, saying that he would eventually have to get killed off, and it would be too depressing.
Jay Baruchel admitted that despite all of the hilarity and the over-the-top nature, making the movie was actually therapeutic, because he felt that some of the arguments and confrontations in the movie were, on some level, things that the actors have actually wanted to say to each other at some point in real-life.
During the first night, where they are sleeping together in the living room, and they all keep scaring each other, there is a picture on the wall, supposedly painted by James Franco, with the title "geeks" on it. It also contains paintings of characters from the show Freaks and Geeks (1999), which was where Jason Segel, Seth Rogen, and James Franco first worked together with Judd Apatow.
Seth Rogen gave an interview, where he described how the script, written by Evan Goldberg and him, combined real characteristics of the actors, who then produced bizarre alternate versions of themselves, with elements that had absolutely nothing in common with the cast. Craig Robinson echoed this point in a separate interview, when he said that Michael Cera's portrayal in the film, a drug-using, ass-grabbing, utterly obnoxious loudmouth, was "the epitome of NOT Michael Cera."
Seth Rogen stated in an interview, that during production, each main cast member had taken him aside, at one point, and told him that they could not do what he was asking them to do, because it was going too far and getting too extreme. James Franco was the only cast member that never turned anything down.
Originally, Seth Rogen and Evan Goldberg asked Sony for a forty to forty-five million dollar budget, but Sony was nervous about the plot of the movie, and refused. Rogen and Goldberg then asked Sony what amount they would be comfortable giving while still letting Rogen and Goldberg maintain creative control, and Sony said thirty-two million dollars. Rogen and Goldberg accepted.
Evan Goldberg and Seth Rogen revealed that the early rumors, that they had approached Daniel Radcliffe for a part in the movie, and he turned it down, were true. They admitted that it was in the very early stages of writing the script, so not all of the parts were fully developed. Rogen and Goldberg have both stated that they understood why Radcliffe turned it down.
The film was going to be shot in Los Angeles, in order to make it easier for the celebrities who would be doing cameos. However, the location was changed to New Orleans, in order to save money. The only celebrity cameo that was lost due to the location change was Cameron Diaz.
Michael Cera's character was supposedly based on an exaggerated version of himself, in particular to how he felt about being repeatedly typecast as the "Awkward Teenager." He had earlier expressed such frustration to Seth Rogen, who decided to use Cera's distraught feelings over this issue while writing, in order to inadvertently show on-screen, that Michael Cera is not only capable of performing outside his typecast, but that the film industry could be responsible for a hypothetical downward spiral of Cera's life into a dark and dangerous place. Reportedly, Cera was extremely grateful for Rogen's writing and depiction of his character, and would be able to thank him for any future roles for which he is not typecast.
When Jay Baruchel and Seth Rogen are pulling up to James Franco's house, the KRS-One song "Step Into a World" which contains the sample of Blondies "Rapture" can be heard playing. This was another example of foreshadowing in the movie.
Evan Goldberg stated, in an interview with Entertainment Weekly, that around eighty-five percent of the movie was improvised. In comparison, Goldberg said Superbad (2007) was ninety-five percent of what Seth Rogen and he wrote, and Pineapple Express (2008) was fifty percent.
The film appeared to have finished a very successful North American box-office run, falling just short of the one hundred million dollar benchmark for blockbuster status, with over ninety-six million dollars in receipts, then it fell into very limited release by the end of August 2013. While the one hundred million dollar blockbuster goal is no longer considered as unique, or important, as it once was (due to the combination of higher ticket prices and film budgets, as well as the majority of most major films taking in most of their box-office revenue from international markets), Sony Pictures put the film in over two thousand additional theaters for the week of September 6-12, 2013, specifically to aim at getting over the nine-figure benchmark. On September 14, its ninety-fifth day in theaters, it officially reached blockbuster status.
Originally, there was going to be a joke where one of the characters said that they had smoked crack with Whitney Houston. When Houston died, the joke was cut, out of respect, and a different joke was used. In addition, while making the film, Seth Rogen and Evan Goldberg were in the process of convincing Prince to let them use the song "Purple Rain", for when Rogen and Jay Baruchel make their way to Heaven. After Houston passed away, Rogen and Goldberg dropped negotiations with Prince, and instead decided to use Houston's version of "I Will Always Love You" in those scenes, as a tribute to her.
In a June 2014 interview, Channing Tatum talked about filming his cameo role as a submissive sex slave to Danny McBride's character. Tatum said that during the sequence where McBride and his cannibal gang eat James Franco alive, he was shown holding up Franco's severed foot and drinking all of the blood that poured out of it. However, when Seth Rogen screened the film for test audiences, their response cards were unanimously disgusted by this image. Rogen said it was the only one of the many gruesome and depraved elements of the film they had a problem with, and specifically noted they did not want to see Tatum doing something like that. As a result, Rogen and Evan Goldberg cut the image. That is why Tatum appears to disappear abruptly from his scene, since there was no other footage of him available, from the point where Franco was murdered.
There was never supposed to be a scene in Heaven. The movie ended when the beams faded to white. Test audiences did not like that they never saw what heaven was like in the movie, so Seth Rogen and Evan Goldberg wrote a new ending and asked the Backstreet Boys to come film it.
As Jay Baruchel and Seth Rogen are in Rogen's living room, a "devil" action figure or doll can be seen on the top left hand side of the the television unit; it is an exact replica of the devil that appears at the end of the movie.
While in Seth Rogen's house, The song "Everybody (Backstreet's Back)" by the Backstreet Boys is played in the background. This song is later performed by the Backstreet Boys themselves at the end of the movie.
In the finale of the movie, Jay Baruchel and Seth Rogen arrive at the gates of Heaven and are given halos by Craig Robinson. A few minutes later, the halos for all three have disappeared. When the members of the Backstreet Boys band arrive to perform, they, too, have halos, but soon afterwards, the halos disappear.
There's several counts of foreshadowing throughout the film, including: A sinkhole appearing on the news on the TV while Jay and Seth are talking about going to James Franco's house, foreshadowing the giant sinkhole that appears outside of James Franco's house during the start of the apocalypse; The Backstreet Boys song playing while Jay and Seth are goofing around, foreshadowing that Jay likes the song and that's why he wishes for it to play later in Heaven; and the discussion between Seth and James about a sequel to Pineapple Express and how the ending would go, foreshadowing the demise of James later on in the film.