Answer: It depends on a person’s development. We see that children cannot display complex feelings: They are either happy or upset and cry, again and again, instantly moving from one to another. A serious grownup, on the other hand, understands that there are different states in life and one can feel both joy and sadness.
A whole person understands creation and knows how to connect its ends, so the worst feelings on one end and the best feelings on the other end support one another and intensify one another. He understands that this is how the matter of creation is arranged, in contrasting poles of darkness and Light, and that they must both exist one opposite the other.
If a person feels that this system exists and operates between these two ends, he is happy that he has both the force of evil and the force of goodness and that they don’t extinguish one another. By connecting on the middle line, the right and the left lines do not extinguish or nullify one another, but rather, support and amplify one another by 620 times.
From the Talk at the Meal 1/26/14