Dealing with the difficulties of life is what makes life difficult.
And for a great many of the world, life is difficult. They try so hard and work so hard, and yet are never able to find happiness. Because whenever they are at last feeling good about their situation or about their life, SOMETHING happens; some problem arises or some situation ends, or some condition changes. And all they loved and worked for in their life is different If not worse.
And no one likes different.
Different is scary. It's rarely prepared for and so infrequently expected. They just thought their life would continue as it is; that their relationship would last "forever" and their job was guaranteed. They thought their health was a certain and their success a given.
But that's not the case.
The world lives by change. And so the greatest cause of our collective depression is the inability to cope with this change. It's the inability or unwillingness to ACCEPT that things are different and that they must be so.
We fight it. We resist it. That resistance is depression; the idea that we can make it all better if only we do this, or that we can change it if only we can manage that. All because we refuse to accept change as reality, and instead cling to whatever past happiness we had, or future happiness we hope.
The Roman philosopher and Emperor Marcus Aurelius once said that we must accept all that comes to us, because what could we have needed more?
What he means is that everything happens as it should, and because it DID happen, then it was the RIGHT thing to happen. It is useless and depressive to think otherwise, to fight and struggle against the reality we refuse to see and the change we refuse to accept.
Acceptance is the key to life and to all that happens to us, may happen to us, or will inevitably happen to us. Break ups. Illness. Age. Death. We must all endure these trials, and if we're to endure them at all we must accept them. We must learn to live with them and move on, because the universe will move on, whether with us or without us.
Better to go with the flow of life than against it. Better to love your life now than to pine for the past. Better to take this challenge and all challenges and defeat them, rather than resist them.