For those who don't know, Murphy's Law states: "Anything that can go wrong, will go wrong." There are those who say that Murphy was an optimist. Personally, I think Murphy's Law gives a very good general view of how, despite one's best efforts, one often just can't win.
I find Murphy's Law to be very much an influence in my life, in regards to how easily even some of the simplest of operations can lead to disaster. So much of an influence, in fact, that I typically refer to myself as an "Avatar of Murphy" (where an avatar is defined as a "bodily manifestation," according to my dictionary). However, while I am an Avatar of Murphy, I do not claim to be the Avatar of Murphy. I only know of one other (Ethan Deneault, for whom I do not currently have a working link to a home page), but there are more than likely a number of people in the world who would count themselves in our number.
However, while Murphy's Law works well as a general case, I've found it better to quote from a more specialized set of Corollaries. Eventually, once I get enough time, I intend to compile, collate, and present my list of Murphy's Law Corollaries. In the meantime, you can check out Peter's Laws ("The creed for the Sociopathic Obsessive Compulsive") as a counterpoint to Murphy's Law.