Phyllis Smith came out of retirement to reprise her role as Sadness for this movie. She requested that Pixar find her a recording studio in Missouri, as she had no intention of traveling all the way to Los Angeles just for that.
Anger has a small "swear jar" with coins in it on the shelf next to his bed.
An early draft of the screenplay introduced the following new color-coded emotions: Freedom (white), Love (magenta), Passion (cyan), and Strength (black). They were later deleted from the film, and replaced with Anxiety (orange), Embarrassment (pink), Ennui (indigo), and Envy (turquoise) instead.
Envy is the only emotion who has only four fingers on each hand. The rest have five.