This happy-thought rule unfortunately is an indicator of a Ponzi scheme or cult, this admonition to only be "positive" and avoid "negative" thoughts.
To tell you the truth, I don't even know what that means. Who determines what's "positive" or "negative"? As real estate mogul & guru John T. Reed has said, (if I may paraphrase) "I don't care if information is pessimistic or optimistic. I only care that it's accurate." I agree. Do you really want to filter out all displeasing information? At your peril.
Suppose I'm driving down the highway and you are my passenger. Up ahead, you see a large wooden box that has fallen off a truck into our lane. Is it "negative" for you to point that out to me? Certainly. But not nearly as negative as crashing into the box. It would be accurate for you to say, "Look out! There's a box in the road!". It would also be accurate for me to decide that it would be better to avoid that box than to smash into it. It would be no time for smarmy value judgments or magical thinking like "Think positive and the box will disappear!".
Which is why you should write your Congressional representatives and insist they support FINRA's** "CARDS" program. CARDS stands for "Comprehensive Automated Risk Data System", the main purpose of which is to catch crooks in the act, in real time, instead of years later. Naturally, the financial industry says CARDS would be "burdensome" (it wouldn't) and jeopardize investor privacy (wrong again). What it would actually jeopardize is Wall Street's insider profiteering at investor expense.
It is good enough for me that the Consumer Federation of America* supports the CARDS proposal. Don't believe the fear mongering from the brokerage community. CARDS will level the playing field back in the direction of you and me. After all, if we're going to spy on people, why not spy on those who handle other people's money?
** Financial Industry Regulatory Authority
*An association of hundreds of pro-consumer groups