Empty skies.

You are a bird.
It doesn't matter what kind of bird so long as it isn't a flightless one. (Ostrich, chicken, etcetera)
Each day you wake with one main goal: to fly high and fly even higher than yesterday. Everyone else is a bird with the same idea in mind. And in order to fly higher than normal, you need to find and share special and unique feathers that are hidden around the world to add to your wings. Not all these feathers are good and some can only be used once one is ready for them. (Based on strength, wit, achievements, you name it)
Now imagine that you were born with a birth defect in your wings, making it tougher for you to fly. You find plenty of feathers, but the majority you add and test out don't go well with your wings and cause you to crash back to earth time and time again. You don't know why that is because you subconsciously forget this disability of yours with so much going on in the world around you only to remember it again later, and strive to do better. Some days you take a colored markers and draw fake feathers on your wings to "look" like you are improving to convince others all is well. And then other days you just give up the hunt resorting to walking on the cold hard ground.
You want to fly as high as everyone else. You want to succeed. But this dilemma pulls you down a lot, literally. Yet, you understand that other birds have their own troubles and some never make it even ten feet off the ground! (these would be the flightless birds, of course)
So you keep quiet about your worries, isolate yourself, and waste time with activities in order to distract yourself from this perpetual obstruction. You don't know where your life will lead at this rate and that starts to kill you ever so slowly.

That defect is depression.
That bird is me.