God has put within each of us a yearning to be happy and content—and that’s not necessarily wrong, when we seek it in the right way. But true happiness only comes from God—and when we seek it apart from Him, it won’t last. Jesus said, “Blessed are those who hunger and thirst for righteousness, for they will be filled” (Matthew 5:6).
I respect your sincerity—but I can’t agree with your definition of sin, because you’ve left God out of the picture. Sin is far more than negative thoughts; sin is anything we do that’s wrong in the eyes of God. It may be a wrong action, or a hurtful word, or a selfish motive, or a failure to do something we should do. Sin is like a deadly cancer, destroying our souls and cutting us off from others—and from God.
But I also can’t agree with your definition of sin because it ignores the reality of human suffering. All the positive thoughts in the world won’t bring hope and healing to those who are victims of injustice or sickness or famine or war. But Christ can give us the love we need to help a hurting world.
My prayer is that you will face honestly your own need for God’s forgiveness. God loves you; He loves you so much that Jesus Christ gave His life to make your salvation possible. Don’t be deceived, but open your heart and life to Christ’s transforming love today.