I have been looking for this citation, on and off, for months. Thought it was either from the New York Times or Wall Street Journal, but can't find it, so maybe I'm wrong. If one of you have it, please share!
It was an article about luck. It said that people who believe themselves to be lucky often do wind up lucky, in part because they keep looking for solutions to problems long after the people who believe themselves to be unlucky give up. In other words, optimism yields luck.
Here's an example of this phenomenon from my own life. Years ago, when I lived in the suburbs, I used to do the suburban thing and park at a train station and take the train into Boston. Like most writers, I'm a late riser and so by the time I got to the commuter garage it was invariably full. Believing myself to be lucky, though, I would drive around a bit longer believing that something would turn up - and it often did. I'd either catch someone leaving a space, or a few times the garage attendant let me park in an unused e-car space, or there were little unofficial niches on the property where i could squeeze my Corolla in and park without getting a ticket.
The other part of being lucky is not minding too much when you're not. When I didn't get a parking spot I wouldn't tell myself, "You're unlucky," but "Oh well, no one's lucky 100% of the time, and this particular instance of not being lucky isn't so meaningful."
I'm not saying that this is a rational attitude - only that it was an effective one, in terms of maximizing the odds that I did, indeed, get to park.
Here's a story that illustrates another theory on luck:
My husband and I were moving, a few years back, and had to move about fifty boxes of books up from the basement out to the garage. Just at the moment we were contemplating that awful task, three of our foster kids showed up. They were adults at the time, living away from home, and the visit was a complete surprise. They are big, strong guys, and of course they made short work of the boxes. After they left, I told my husband that my new-age-y friends would have said that we "manifested" the kids when we needed them. His inimitable reply - because we hadn't yet finished packing: "See if you can manifest them again tomorrow."
I'm not very new age-y myself, so I will work more on optimism than manifesting.
You should cultivate optimism, too!