But the people gushing over this Pixar film for its "originality" are saying "its the most original PREMISE I've heard!!", rather than praising the film for its execution.
The execution may be very different than the 90s sitcom, that doesn't change the fact that the "Every day person's emotions are personified as characters who clash with one another inside the person's head" has been done before.
It’s been done in medieval morality plays too.