A second characteristic of discouragement is that it is recurring. Being discouraged once does not give you an immunity to the disease. You can be discouraged over and over again. In fact, you can even be discouraged by the fact that you are discouraged a lot. There is no antibody which can be injected to give you immunity.
Discouragement comes and goes and comes back again.
A third characteristic of discouragement is that it is highly contagious. Discouragement spreads by even casual contact. People can become discouraged because you are discouraged. You can become discouraged because other people are discouraged. You might be familiar with the story of the man standing on a bridge prepared to jump to his death.