Claude Sautet's films are always rich in introspective thought, whether the subject is the fragility of existence (Les choses de la vie), the unconditional love of a man toward a woman that wants out of a relationship (César et Rosalie) or the everyday struggles to make it through ordinary existences (Vincent, François, Paul et les autres). In Un mauvais fils, Patrick Dewaere is paradoxely a good person who has made very bad decisions, but now wants to make amends and get a better life, all the while his father is still grieving the death of his wife.
Remarkably, while being usually casted in loser roles, Dewaere redeems himself from loser status to become a good son, a reliable worker and a strong support of his addicted girlfriend. It's too bad that we lost this prodigious actor too early, struggling himself with addiction and depression.