Explain, in your own words, the theme of "A Poison Tree".

"A Poison Tree," a poem by William Blake, explores the theme of anger and its consequences. The poem contrasts the healthy expression of emotions with the destructive nature of bottled-up resentment. The speaker initially talks about being honest with a friend, which leads to resolution, but when anger is harbored towards an enemy, it festers and grows. This unresolved anger transforms into something toxic, symbolized by the "poison tree," ultimately culminating in betrayal and harm. The poem illustrates how unaddressed emotions can lead to negative outcomes, highlighting the importance of communication and the dangers of nurturing hatred. Overall, it serves as a cautionary tale about the impacts of suppressed feelings and the need for open dialogue.