Walt Whitman, one of the greatest of American poets writes in, "Crossing Brooklyn Ferry" of his capacity for evil:

I am he who knew what it was to be evil,

I too knitted the old knot of contrariety,

Blabb’d, blush’d, resented, lied, stole, grudg’d,

Had guile, anger, lust, hot wishes I dared not speak,

Was wayward, vain, greedy, shallow, sly, cowardly, malignant,

The wolf, the snake, the hog, not wanting in me,

The cheating look, the frivolous word, the adulterous wish, not wanting,

Refusals, hates, postponements, meanness, laziness, none of these wanting, ...

Source: Walt Whitman, “Crossing Brooklyn Ferry (Leaves of Grass)” Public Domain, PoetryFoundation.org (1860-1861)