I'm trying to identify a science fiction story which I believe was written sometime before 1960. It was probably a "novella" -- dozens of pages in length, but definitely not published as its own little book. (I read it in an anthology, the title of which has also slipped my mind.)
In the first several pages, the following premise is established:
The protagonist is a wealthy man, living in what appears to be a standard-issue "modern American city" ("modern" by the standards of the mid-Twentieth Century). In recent years, he has had incredible good fortune, consistently! This was not true in the first twenty-odd years of his life, but then something changed dramatically, so that now he seems to lead the proverbial "charmed life."
For instance, we see the man reminisce to his trusted chauffeur about a time when he was riding the rails from one city to another, basically a hobo who couldn't afford to pay for train tickets, and then a couple of guys started to threaten him. Suddenly, he says, several other men (complete strangers) arrived on the scene, pounded the would-be muggers until they were unconscious, and then the rescuers disappeared as quickly as they had arrived, without even bothering to introduce themselves or say "you're welcome!" to the protagonist.
Since then, he's had further incredible luck -- the Midas touch, you might say. He found a good job, he somehow started accumulating wealth, and now it seems as if every time he invests in a stock, its value goes up pretty soon. (Or sometimes, if the stock doesn't go up, the man's brokerage house apologetically tells him that there was a silly clerical error, and someone bought or sold the wrong thing in his name, with the happy result that his investment portfolio still made money from the actual fluctuations of the market over the next couple of days.)
The protagonist has become highly suspicious about so many incredible coincidences which always seem to work in his favor. He hypothesizes that there is some sort of vast conspiracy which is dedicated to spying on him and keeping him as happy as possible . . . but, for some reason, the conspirators don't dare tell him exactly what they are trying to accomplish, and why! Instead, they apparently want him to just assume that everything happens in his favor "by accident."
As the plot progresses, it is revealed to the reader that these suspicions are right on target. The protagonist, or something lurking within him, is basically a godlike entity which is capable of reshaping the entire universe on a whim, but of course the protagonist is not consciously aware of this potential. The conspiracy has somehow become aware of the situation, and is frantically trying to keep him soothed so that he won't get psychologically agitated and destroy the status quo of the world as we know it. Unfortunately, they've seriously overdone the "protect him from stress" bit, and now the very fact of his nonstop good luck is making him feel increasingly stressed!
A note: The story in question definitely is not Robert A. Heinlein's "They," nor is it Charles L. Harness's "The New Reality." (For that matter, it just now struck me that the basic situation bears some resemblance to the premise of the much later Jim Carrey movie "The Truman Show," although Truman did not possess superhuman powers.)