The bathtub scene between Jason Segel and Ed Helms was all improvisation. Jay Duplass and Mark Duplass allowed the actors to riff for 40 minutes straight before calling "cut".
Ed Helms didn't care for the screenplay when he read it for the first time but he was intrigued by the prospect of working with the Duplass brothers and Jason Segel.
Jason Segel was attracted to the project because the character of Jeff - a fairly inert man who likes to go with the flow - reminded him of himself as a younger man.
Directors Jay Duplass and Mark Duplass claim to have cried through the entire premiere of this film.
Jeff is "living in his mother's basement", but that would be very unusual in Baton Rouge: thanks to a shallow water table, tough clay soil, and extreme humidity, buildings there are rarely built with basements. The same is true of nearby New Orleans, where co-directors Jay and Mark Duplass grew up, and where the movie was shot.