A Poison tree

“A Poison Tree,”  is a poem by William Blake where the tree is used as an extended metaphor, to explain a truth of human nature. This poem teaches how anger can be dispelled by goodwill or nurtured to become a deadly poison. 
Here it goes,

I was angry with my friend:
I told my wrath, my wrath did end.
I was angry with my foe:
I told it not, my wrath did grow.

And I waterd it in fears
Night & morning with my tears;
And I sunned it with smiles,
And with soft deceitful wiles.

And it grew both day and night,
Till it bore an apple bright.
And my foe beheld it shine,
And he knew that it was mine,

And into my garden stole,
When the night had veiled the pole;
In the morning glad I see
My foe outstretched beneath the tree.

William Blake

This is such a wonderful demonstration of how we let and nurture hatred and anger inside us. As Buddha says, Holding on to Anger is like holding a hot coal road in an intention to throw it at someone else, but eventually we are the one who gets burnt. The life that is around and inside us can get way better by getting rid of these self-poisoning attributes.