Barbara Ehrenreich has just written a book on this very subject called, "Bright-Sided" and it sounds like a must read.
"A sharp-witted knockdown of America’s love affair with positive thinking and an urgent call for a new commitment to realism
Americans are a “positive” people—cheerful, optimistic, and upbeat: this is our reputation as well as our self-image. But more than a temperament, being positive, we are told, is the key to success and prosperity.
In this utterly original take on the American frame of mind, Barbara Ehrenreich traces the strange career of our sunny outlook from its origins as a marginal nineteenth-century healing technique to its enshrinement as a dominant, almost mandatory, cultural attitude. Evangelical mega-churches preach the good news that you only have to want something to get it, because God wants to “prosper” you. The medical profession prescribes positive thinking for its presumed health benefits. Academia has made room for new departments of “positive psychology” and the “science of happiness.” Nowhere, though, has bright-siding taken firmer root than within the business community, where, as Ehrenreich shows, the refusal even to consider negative outcomes—like mortgage defaults—contributed directly to the current economic crisis.
With the mythbusting powers for which she is acclaimed, Ehrenreich exposes the downside of America’s penchant for positive thinking: On a personal level, it leads to self-blame and a morbid preoccupation with stamping out “negative” thoughts. On a national level, it’s brought us an era of irrational optimism resulting in disaster. This is Ehrenreich at her provocative best—poking holes in conventional wisdom and faux science, and ending with a call for existential clarity and courage."
...........and from Thomas Frank:
“We're always being told that looking on the bright side is good for us, but now we see that it's a great way to brush off poverty, disease, and unemployment, to rationalize an order where all the rewards go to those on top. The people who are sick or jobless—why, they just aren't thinking positively. They have no one to blame but themselves. Barbara Ehrenreich has put the menace of positive thinking under the microscope. Anyone who's ever been told to brighten up needs to read this book.”—Thomas Frank, author of The Wrecking Crew and What's the Matter with Kansas?
http://ehrenreich.blogs.com/