The episode describes about Mrs. Pumphrey's silly actions. She's wealthy but lonely, and she dotes on her dog, feeling a strong emotional bond with him.
Because of her excessive care, the dog becomes very overweight and gets sick. Mrs. Pumphrey was overly protective, but her indulgence was foolish. Despite warnings and instructions from Mr. Herriot, the vet, she ignored them.Tricki became ill and needed treatment because of this. I believe people like her can unintentionally harm others, as her foolishness put Tricki in trouble.