What many people call depression ultimately boils down to two things: either they see no hope or they feel they've been treated unfairly. Essentially, it's a disconnect between expectations of reality and reality itself. Sometimes, the problem isn't the thing itself, but how you look at it. As long as you can 'shift your perspective', look at it from another angle, and detach yourself from personal gains and losses, many emotions will loosen up. If you zoom out a bit further, look at it from the perspective of how the world operates, or even observe nature and the way animals survive—competing for resources, survival of the fittest, that's just how it is—when you truly understand this point, many things in the human world no longer seem so 'insurmountable'. It's not that the world has gotten better, but that you've stopped demanding it to be 'absolutely fair and smooth'.