The relationships of Joy from the Inside Out franchise
Friends
Sadness
Since their first meeting, Joy soon became fond of Sadness because she made Riley cry on occasions when bad things happened to her, their friendship would soon grow more when they get lost in Riley's mind and decide to return to the headquarters so she can let Sadness make Riley feel remorse and return to her parents.
Their friendship grew little by little, as with her help, she helped her create memories of Riley by combining their characteristics, also the two also have something in common so Riley feels if she is suffering something that could happen to her, on the other hand, in the sequel, Joy takes Sadness to the belief system to show her about how memories work to create Riley's sense of Self, also, Sadness is afraid of ruining things like she did in the first movie, but Joy still has faith in her and her various work.
Anger
Joy and Anger can sometimes be seen from one example to another, but in the sequel, their relationship takes a step forward, as the emotions search for unpleasant memories to discard, Anger shows him one where Riley doesn't remember the name of a girl he met, then gives Joy said memory to discard, however during the way back to the headquarter, an argument between him and Fear and Disgust reached the extreme when he called Joy "Delusional" causing Joy to lose patience and reprimand them for arguing instead of helping her, feeling remorse for this and realizing that her arguments with Disgust and Fear would not solve anything, Anger told Joy that she made many mistakes along the way and that she will continue to make more in the future, advising her that if she let it get the better of her, they could give up easily, this led Joy to recover and continue her journey to the headquarter to stop Anxiety.
Fear
Joy's first encounter with Fear led him to learn the latter's meaning in protecting Riley from any danger, as when Fear stopped Riley just in time from tripping over a wire, Joy, along with Sadness congratulated him on his recent feat, over the days, Fear helped Joy keep Riley safe and sound from any danger that might happen to her.
In the sequel, Fear and Joy still maintain their teamwork to help Riley feel safe, as in the moment when during the Hockey game, Fear said that Riley needed the mouthguard, only for Disgust to snatch the control from her saying that it is not Riley's making her spit, for that reason Joy and Fear helped Riley in the Hockey game to help her win, during the trip back to the headquarters, Fear continued to help her throughout the journey, such as creating together with her, Disgust and Anger, positive scenarios so that Riley can sleep well at the Hockey camp, while Anxiety forced all the mentalers to create negative ideas, the actions of Joy and Fear help Riley feel safe and protected from any harm that may cause her.
Disgust
When Joy first met Disgust, she witnessed her prevent Riley from eating broccoli for breakfast, this is stated because Disgust makes sure Riley don't gets "poisoned" physically and emotionally, on another occasion, while Riley was at school, Joy tried to get Riley to eat a grape off the ground, but Disgust tried to stop her by fighting for control of the console, and only let go when Joy told her something that seemed disgusting to her, in the sequel, the development of their relationship is much superior than that of the first film, during the moment in which Riley met Bree and Grace, she tried to get Riley to help her with her project, but when Disgust stopped her by saying that it was a "Social Titanic", she decided to ignore her and let Riley help Bree and Grace, which excited both emotions, during the night, while the emotions searched for unpleasant memories, Disgust found one where Riley met A boy who dated her but doesn't remember his name, leaving Joy with that memory to throw away, however, when Anxiety took over the headquarters, and the emotions were trapped in the vault, Disgust met Lance Slashblade, but Joy reminded her that the power move was unpleasant which is why he's in the vault, but Disgust assured her that Lance has potential, from it, their relationship grows with each moment they spend together with Anger and Fear during their journey.