If you've ever been particularly depressed you'll be aware of how it warps your perceptions.
Suddenly the whole world is cold and bleak and hostile, it's hard to get out of bed in the morning and its even harder to do anything useful once you do. Your mind finds a way to see the worst in everything and you become blind to to the brighter side of things.
Conversely, if you've ever been really happy (and I should hope so!) you'll know how all the darkness disappears and all your fears and worries evaporate in the sunshine of optimism. Suddenly you become full of the energy to do all those things you've been meaning to, and they always prove so easy too!
Neither mindset is entirely rational, let's be honest, but there's little you can ever do about it. Our experience of the world is always viewed through the lens of our mindset, and that mindset is generally very fickle indeed.
So if you are feeling depressed right now, sit back and don't enjoy the show, you think it's crap anyway, but do be aware that sooner or later you may well be seeing things differently.
EDIT: Thank you very much to all you lovely people for commenting, faving, featuring and following. I appreciate it, cheers :D