You are saved by grace and not by any works that you should boast. Those are hard words for people to hear that feel like they should have to be doing something. Its normal to feel that way.
The parable of the workers is a prime example of sour puss Christianity. The people worked all day in the field and were paid their agreed upon wage. Then of course comes along another person who gets there late and gets paid the same wage because that was the agreement with the owner. Then the others get upset.
Another is the actions of the Prodigal Son. He did not want to rejoice with his Father about the return of his brother who had been gone. He went on to tell the Father that he had never had a party thrown for him. He had always did what his father had wanted. He had never caused him grief. But what was missing is that he probably did not have a love relationship with his father. Why would I say that? If he really loved his father, he would care about how his father had been grieved over the Prodigal sons’ absense. If he was more about knowing and loving his father than just doing what he presumed his father wanted; he would have rejoiced with him.
It is the same way with our heavenly father. He wants a love relationship with his children. Not a performance driven relationship. We are born again solely based on what Jesus did and believing upon that. Thats it. We are righteous in God’s eyes because of what Jesus did.