Core Memory Orbs are vitally important objects from the Disney/Pixar film Inside Out.
These special kinds of Memory Orbs contain a very special memory (like an accomplishment or behavior trait), and it activates/creates an Island that serves as the basis of that person's personality and interest. Core memories are distinguishable from the other memories by their much brighter glow. They are stored in the center of the Headquarters. The core memories can be any from any emotion, but Riley's first five are yellow in color, meaning that Joy is the one who helped create these special memories. But one core memory was created by Sadness on the first day of school when Riley started crying about her move to San Francisco, which Joy immediately tried to get rid of, causing them to accidentally leave the Headquarters. During the events of the film, any memory Sadness touches becomes sad and can't be changed back, so Joy tries to prevent her from touching the core memories.
When Joy and Sadness get vacuumed out of Headquarters, the core memories were with them. Without the presence of the core memories, the islands that build up Riley's personality began to shut down and eventually break down and fall into the Memory Dump.
With the installation of the new controls, it seems that all of Riley's new core memories were formed by two emotions working together.
Riley's Core Memories
Hockey: When Riley was very young, she and her parents were playing hockey on the ice, and when she scored her very first goal, this core memory was created, and it led to the creation of Hockey Island, the island that shows Riley's love for hockey.
Goofball: Riley was known for being a goofball when she was young, this led to the creation of the core memory which would create Joy's favorite island: Goofball Island.
Friendship: It is shown that one of the core memories led to the creation of Friendship Island, where Riley and Meg are walking side by side together.
Honesty: Riley's known for being honest, thus creating Honesty Island.
Family: Riley's memory of her loving parents created Family Island.
Nostalgia: When Riley cried at school, a sad core memory was created. It's unknown what island this would make since it never got plugged in.
Family (Version 2): After Riley rekindles with her parents, another family core memory was created. It is yellow and blue, as both Joy and Sadness created this core memory.
Friendship (Version 2): Anger said that the Friendship Island was expanded and they added the new "Friendly Argument Section".
Hockey (Version 2): Shows a new memory of Riley playing hockey, possibly recalling her talent in it. It is yellow and red, implying that she is now plays aggressively, but still enjoys the sport.
Tragic Vampire Romance: Sadness said the new Island, "I like Tragic Vampire Romance Island." Tragic Vampire Romance Island is a reference to Twilight, a vampire romance movie based on a book.
Fashion: Disgust said the new Island, "Fashion Island!? (gasp) Everyone, shut up."
Boy Band: Fear said the new Island, "Boy Band Island, that's just a phase."