How a person deals with random shit is another story, but it doesn't change the incidence of random shit at all.
People who think they are special because the shit hasn't hit them are annoying. Prosperity gospel Christians are wrong. They make up stories to explain their own good fortunes. But God doesn't love them any more or less than He does the schizophrenic homeless guy standing on the corner yelling obscenities at passing cars. The Universe, Mother Nature, however you want to describe it, doesn't give a fuck about your thoughts or any goodness in your heart. That's why we all have to look out for one another, even the people we observe making "poor choices" or any other judgmental nonsense that excuses our own selfishness and inaction.
My great aunt was an anxious person; nevertheless she lived more than a century in good health with no financial problems, no illnesses, not even a head cold, ever. As a child she lived in San Francisco but she happened to be out of town with her mom visiting family the day of the great earthquake. The rest of her life was equally charmed. She outlived a few good husbands and divorced a few bad ones. Her sister, on the other hand, my grandma, similar to my great aunt in many ways and an equally anxious person, got knocked around by the universe for no reason at all. She lost a young child and the hits kept coming until she herself died of cancer.
Random shit.
I'm the most pessimistic guy you'll ever meet, pathologically so. I take powerful psych meds; without them I'm a danger to myself. I can't even begin to tell you how I've sabotaged my own life. But that's not the random shit I'm talking about.
When I first met my wife she'd just returned to work after yet-another-surgery following a brutal car accident that was not her fault. Nearly all of her medical problems since, including more recent surgeries, can be traced back to that one instant when an impaired driver ran a red light at high speed.
"Positive thinking" isn't a bad thing, but like many human beliefs, it's not a rational thing.