Your Weakness can be Your Strength
The highest level of being slow to anger is when a person’s intellect is the master of his emotions. Such a person has his emotions work for him according to the dictates of morality.
A person who has a naturally cold personality or lack of tendency towards anger has not reached the level of the person who has a natural tendency to become angry, but has control over his temper.
(Hamaspik L’ovdai Hashem, p.43; Rabbi Pliskin’s Gateway to Happiness, p.187)