Gratitude is the foundation of mental health. I have never seen a depressed person who was properly grateful. This is not to say there are not legitimate reasons for depression, but depression tends to skew our perspective.
The point of this observation is not to criticize someone who struggles with depression, but only to state that I must maintain a state of gratitude in order to protect my own sense of wellbeing. If existence is as precious as I perceive, then every moment is an opportunity to exult in my “now-ness”. I fear that if I do not maintain an abiding sense of gratitude, I will fall prey to the terrors of reality.