During the days of Sefirah, the Rebbes of Belz focused on the Middah of Anavah – humility, to prepare for Kabulas Hatorah. Anavah is the beginning and end of all the Middos. If someone is humble and not self-centered, all good Middos will follow.
The Orchos Tzadikim started his Sefer with the Middah of Anavah because of the above reason. Anavah is the core of all Middos Tovos. Even Ta’avos (desire for consumption), Atzlus (laziness), and Atzvus (low spirit and despair) are fruits of self-centeredness.
The Ba’al Hatanya’s first teaching in the Sefer Likutei Amurim Tanya tells us, that every person has an animal soul and a soul that is a spark from Hashem. The animal soul constitutes good and bad Middos. The G-dly soul has all the Middos and Ohros that connects a person to Hashem.
The vast majority of people can’t change (אתהפכיא) their animal soul; only Tzadikim can. Everyone else, the “Beinoni”, can overcome (אתכפיא) their animal soul and bring the G-dly soul to reign like a rider on a horse. A person can overcome their animal soul not only that they shouldn’t come to a bad action, but also that it shouldn’t even have an expression in their feelings and thoughts.
That is our primary Avoda; to overcome our animal souls through Torah, Tefillah, and Mitzvos. The holy Mitzvos purify us so we are able to overcome the animal soul.
A “Beinoni”, even if they can’t change their animal soul, they can change a behavior pattern and even emotions so that the bad Middah becomes mute and the good Middah is what the person is used to. Still, the animal soul is there and if the person is not aware and let’s himself be dragged in, the bad Middah can pop out.
This teaching helps us in many ways. First, even if a person is older and finds that they still have the bad Middah that they worked on all their lives, one should not despair. That is how Hashem made us. Our work is to 1) make sure that the animal soul is not taking over our feelings or thoughts and of course not our actions. 2) To accustom the animal soul that Avodas Hashem is Geshmak, and even if self-control is sometimes difficult, at the end it’s sweeter than all the sweets in the world. The animal soul can also understand this.
Another point, instead of focusing on breaking the bad Middah, Chassidus focused on elevating the person and learn to transcend the Middah, to make the G-dly soul the rider and the animal soul the horse. When a person is busy with Avodas Hashem and is focused on Hashem, they become less self-centered and less focused on their bad Middah. Also, the animal soul can become a tool for Avodas Hashem when properly used.