Humans pursue the Quest for Happiness during all their lives. Some reach a satisfactory state, some happen to go even further but very few actually reach it.
It's because few people understand what brings happiness.
What hinders happiness is suffering. Suffering brings fear and doubt. Suffering is caused either by the pain which others causes us or by the remorse we know whenever we inflict pain onto others. In the first case, we feel a lust for vengeance while in the second we feel much regret.
Nobody can pretend to know happiness by being the only one above the others. He will inevitably fall and suffer. But if all advance together toward happiness, they will then get closer to it.
The faithful knows that only the forgiveness will bring him along the Faith Rise Grace path because it's the only way to sincerely evacuate the sour taste of suffering.
Of course, true forgiveness is a rare virtue which only the Saints possess. Their example shall inspire us in our daily lives.