Use it when discussing sensitive subjects that might upset people or start disputes. Regarding the company's layoffs, the less said, the better.
Pro Tip 2/3
Avoid Detail
Suggests that providing more detail might cause unnecessary complications or embarrassment. When asked about the divorce, she remarked, the less said, the better.
Pro Tip 3/3
Conveys Disapproval
Implies disapproval or dissatisfaction with a situation without giving blunt criticism. His response to the scandal? The least said, the better.