What according to beatty was clarisses "one talent"?

Beatty described Clarrisse as a "do-gooder with their shocked, holier-than-thou silences, their one talent making others feel guilty".

She was very innocent, sweet, and happy, unlike the rest of society.

Explanation:

The exact quotation in the book was "One of those d** * do-gooders with their shocked, holier-than-thou silences, their one talent making others feel guilty."