I have encountered this sentiment in one form or another since 2003. This idea that, if you are unhappy, it might just be because you are causing yourself to be unhappy by failing to "count your blessings," or think on nice and wonderful things, or because you're just not looking at the bright side like you should be. This idea that it's not the place, it's not the circumstance, it's not the sorrows like battalions and the avalanche of eventualities caught in the tornado whipping around you that flap their black wings and spit blood in your eyes while screeching profanities at the top of their whiny voices - it's you.
I have come to the conclusion that this is a bullshit sentiment expressed by delusional people, pretty much exclusively. They don't know they're delusional - if they did, they wouldn't be. But they are, nonetheless, and often, I think, it is a kind of self-imposed delusion disguised as a part of half-assed mental therapy. "This is one of the things I do to keep me positive." These are people with the idea that simple appreciation of that which is positive will be enough to keep a person happy. A simple person, perhaps. For anyone else, appreciation of a thing will lead to the analysis of that thing, and that cannot always be a positive experience, if it is meant to generate real data.
Don't misunderstand - I'm a huge fan of appreciating the good in a particular situation. I want to be happy. However, I'd rather enjoy my cigars at peace with the idea that I might someday get throat cancer, instead of purposefully and consciously not thinking about it, being a participant in my own ignorance and denial. I also think we do ourselves a grave disservice by not taking time to focus on the bad - how else to analyze and correct, or simply make a change to a situation that removes you as a participant? How often are people mobbed up in harmful bullshit for too long while they tell themselves "everything's cool?"
Further, I would posit that the idea of being too comfortable with the way things are is contrary to almost everything valued and noble in the human experience. Why become enlightened, or seek salvation, if things are fine the way they are? Why strive for change? Why fight for freedom, independence, or individual self-determination? Why educate, or be educated? Why move, why discuss, why progress? Why experience at all? "Look at what there is - what need is there for otherwise?" Bullshit. Without a historical bucking of the status quo, there is no achievement. What would be the need? Things are fine.
I am sick to death of the sentiment. Encouraging people to focus solely on the good, without balanced thinking on the other side of the equation is a boot on the neck of the human experience. It leads to sedentary lives filled with inaction, a lack of pure, unmuddied thought and feeling, no analysis of situations and thus, no learning, and, most importantly and most irritating, a kind of forced, premature inner peace that the proponents of this idea didn't work for, and do not deserve. That kind of peace is death, whether you know it or not, and whether or not it catches up with the physical right away, it is death in an armchair, looking at the fucking ceiling, blissed out on the perception of blessings, telling itself not to question, seeking only the wonderful, ignoring all else.
What a bunch of shit.
But then, I'm probably just being negative.