Why is the St Elsewhere series finale so hated?

The series finale of St. Elsewhere is often criticized for its controversial twist that reveals the entire series was a product of the imagination of an autistic boy named Tommy Westphall, who is staring at a snow globe. Many viewers felt this ending undermined the show's complex narratives and character development, reducing the rich storytelling to a mere figment of a child's mind. Additionally, the finale's surreal and ambiguous nature left fans feeling unsatisfied and frustrated, as it seemed to dismiss the emotional investment built over the series' run.