The poem "A Poison Tree" by William Blake is about the suppression of anger and how it leads to increased anger over time. It is told from the first person perspective of someone who was angry with both a friend and a foe. When angry with the friend, telling them resolved the anger. But anger toward a foe grew as it was kept secret, nourished with tears and deceitful smiles, until it manifested as a poisonous apple that killed the foe.