Recently watched a TEDtalks video about depression and remember the speaker saying something along the lines of "depressed people often feel that 'normal' people look at life behind a veil of optimism and happiness, whereas the depressed believe they have this veil removed and see reality as it really is."
Not the actual quote, but the gist of what he was saying as I remember it. Even though I suspect I'm not actually depressed, I feel that I can relate to this idea, since I usually think that way, as false as it may be.