Both Iago and Hamlet’s resentment is the original emotion. But Iago`s emotions reach resonance, so they are strong, free and lead to action
“Hamlet” is the story about a dutch prince who got so offended by the whole world that he destroyed himself, all his family and friends and ruined the kingdom.
Resentment is essentially suppressed anger. Anger that we experience, but do not express. Unexpressed anger turns against us.