Notice how toxic anger and bitterness can be? I've made some really bad, un Godly, life changing decisions out of anger. As I started a closer relationship to our Lord, thru prayer, God gave me the strength to get rid of alot of anger.
Ephesians 4:31-32 ESV / Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you.
I can honestly say that AS SOON AS I made this choice I felt at peace, and I was able to feel love for those that caused me pain.
"But I tell you: Love your enemies and pray for those who persecute you" - Matthew 5:44 (NIV translation)
Also, bitterness or holding grudges and not forgiving others can hinder our prayers to God.
Mark 11:25-26 (New International Version)
25And when you stand praying, if you hold anything against anyone, forgive him, so that your Father in heaven may forgive you your sins."[a]
So pray for the strength to forgive those who hurt you. Pray for those that hurt you!