While I'm not at all surprised that P.L. Travers hated the Mary Poppins movie...

...I didn't know it got quite this ugly.

From mental_floss:

Despite having script approval, Travers’ edits were largely disregarded. Travers loathed the movie’s animated sequences and was perturbed that Mary Poppins’ strict side was downplayed. After some heated meetings, Travers reluctantly approved. She would have been shunned from the star-studded premiere had she not shamed a Disney exec into an invite. The 65-year-old Travers spent most of the movie crying and ultimately refused to let Disney touch the rest of the series.

UGH.