Margaret White's performance in the original film "Carrie" (1976) was highly acclaimed primarily due to the intensity and depth brought to the character by actress Piper Laurie. Here are several reasons why her performance stood out:

1. Character Intensity and Complexity: Piper Laurie portrayed Margaret White, Carrie's deeply religious and domineering mother, with a chilling intensity that made the character memorable. Her ability to balance the extreme religious fervor with genuine love and fear for her daughter created a complex, multi-layered character.

2. Physicality and Presence: Laurie's physical portrayal of Margaret, including her body language and facial expressions, effectively conveyed the character's fanatical nature. The way she carried herself added to the menacing aura that surrounded her character.

3. Emotional Range: Laurie was able to express a wide range of emotions, from stern authoritarianism to hysterical madness. This dynamic performance captured the audience's attention and invoked both fear and sympathy, making the character more compelling.

4. Critical Acclaim and Recognition: For her role, Piper Laurie received an Academy Award nomination for Best Supporting Actress, which highlighted the critical acclaim her performance received from both audiences and critics alike.

5. Memorable Scenes: Many of the scenes involving Margaret White, including her intense confrontations with her daughter Carrie, are remembered for their dramatic tension and Laurie's powerful delivery of lines.

For additional insights, you might want to explore reviews and critiques from the time the film was released, which can provide contemporary perspectives on why Laurie's performance was so impactful.

Source: The Wrap.