Abraham Lincoln used to write angry letters and stow them away, unsigned and unsent [1]. The book "How to Win Friends and Influence People" claims he stopped harshly criticizing people publicly after being challenged to a duel [2] by a government official he had attacked anonymously in the press.

1. https://www.battlefields.org/learn/primary-sources/lincolns-...

2. https://www.battlefields.org/learn/articles/abraham-lincolns...