You do not get to decide the seeds of bitterness in you life but you do get to decide if you water them.
"Be not overcome with evil, but overcome evil with good."~ Romans 12:21
In Hebrews chapter 12 God speaks of the root of bitterness springing forth to trouble man and defile him. In life we get moments when we deal with anger or resentment. We can choose to allow our emotions to fester and grow or we can choose to go to God, and refrain from anger. When we are slow to anger we abound in steadfast love and faithfulness. The more we water the anger the farther away we become from his goodness and mercy.
We tread through our emotions and try to make sense of where they have grown from but by asking God for direction to overcome it, and peace to mend our feelings, we can be a model of Christ's love as God meant us to be. We must learn to not only forgive others quickly but also not forget to forgive ourselves which in many times is where the root of bitterness stems from. You can overcome the root of bitterness and in doing so overcome evil with good for this small action of obedience to His word will bring many blessings to your life. You must make the decision to water the weeds in your garden or flowers and plants.