The designer you can blame for "it's a small world"

Mary Blair. Her name may not mean much to most people, but any Disney Nerd knows her name and her work. She was a concept artist for the Walt Disney Company, designing the colors and moods for many disney films in the 50s and 60s , and creating murals for parks and hotels, and everyone's least favorite ride "It's a Small World."

Look at their sick sadistic smiles

Her designs/artwork is deceptively simple. She used simple shapes but arranged them in such a way that entire landscapes can be seen in charming, mood creating ways. For instance, the colors for small world create an idea of happiness; that the world is bright and full of life and friendship and somewhat stereotypical nationalities.

But it's adorable, so it's ok.

And when she created moods for scenes in the animated features, she was asked to give the key animators an idea how the scene should fear, and then they would reference her painting for the color palette. 

From her pre-production designs and color schemes, animators were able express the mood of a scene as well as they could.