According to the wisdom of Kabbalah, the state of slavery in Egypt means that we are under the complete control of the desire to enjoy for self-benefit alone, or in other words, the human ego.
From such a state, we embark on an inner journey to correct our desire so that we enjoy not egoistically, i.e. for the sake of self-benefit alone, but for the benefit of others and the Creator, which is an opposite desire to ours—to give, love and positively connect.
This inversion of our intention is considered a correction of our nature, and it is described in the Torah as us exiting Egypt and entering the Land of Israel.
This correction of our ego from prioritizing self-benefit to prioritizing the benefit of others and nature describes the spiritual path we undergo until our final eternal and perfect state, called “the end of correction” (Heb. “Gmar Tikkun”).
At every stage of this spiritual path, we need to exit our ego called “Egypt,” and gradually start revealing the force of love and bestowal in nature called “the Creator.” Doing so leads us to great joy and a major surprise that the Creator prepared for us.
Therefore, our need to remember that we were slaves in Egypt means that we were in the desire to enjoy for ourselves alone, which completely controlled us, and that the Creator brought us out from our self-aimed desire. We needed to feel that we could not exit our egoistic desire other than by connecting to one another and reaching a sincere mutual request—a prayer—to exit our ego. We were then granted access to a new nature of love, giving and positive connection with others through which we discovered a harmonious, peaceful and joyous reality.
This feeling is very special because a part of it penetrates our desire to enjoy, and another part resists our desire. With this contrast inside, we can then scrutinize the forces that operate on our egoistic nature, whether and how much we can exit the control of those forces, and how the upper force—the Creator—grants us that special ability.