Life is too rough not to believe in something at the end of the day. It's hard to have relationships with people because people will fall short. People will hurt you. Even if they have the best intentions at heart, people won't always act the way you think they should. Frankly, sometimes people don't deserve you.
We have a relationship with God and we hurt him. We fall short and we don't always do the things we should do. However, God will never forsake you no matter what. Proverbs 24:16 says "A man falls seven times but rises back up again." No matter what you do or how much you hurt the Lord, it's never too late. His mercy endures forever. He will forgive you with no condemnation.
We owe it to God to forgive the people that hurt us. We shouldn't carry a burden of anger around for anyone. We receive all the chances we ask for with God. We owe it to him to follow in the likeness of him and have mercy on the wrongdoers.