You shall not hate your brother in your heart. You shall surely rebuke your neighbor, and not bear sin because of him. You shall not take vengeance, nor bear any grudge against the children of your people, but you shall love your neighbor as yourself: I am the Lord.
The key is whether or not we will be honest before God about our sin. We will either get bitter or better, depending on whether we will acknowledge our sin before God. Have you held anything from God (i.e. deceit) or have been totally transparent?