Here’s the ~inside story~.
Inside Out and Toy Story both open with a group of characters whose main job is to take care of a young child.
Disney / Pixar
The child in each movie is moving, which is a BIG deal to the characters.
Disney / Pixar
In both cases, there's a leader who is upbeat and likes things to go a certain way.
Disney / Pixar
And then there's a second character who doesn't get along with said leader...
Disney / Pixar