Wow, you might think that the “law of Sod” is much older than that, well, I would anyway. The belief in Sod`s Law, which shows a negative view of fate, goes far back in human history. (The Daily Mail) The so-called law is usually expressed as follows: “If something can go wrong, it will go wrong.” A slightly different form of Sod`s Law states that “the degree of failure is directly proportional to the effort expended and the necessity of success.”  Murphy`s Law is a humorous American axiom that says anything that can go wrong will go wrong. The term Murphy`s Law was coined in the early 1950s during the US Air Force`s G-Force tests. One version of the story is that an aerospace engineer named Captain Edward A. Murphy installed a key sensor on the back and skewed the test results. Another version of the story says that Captain Murphy didn`t do such a thing, so the reason he`s associated with Murphy`s Law is because he`s often expressed the idea that anything that can go wrong will go wrong. Eventually, other members of the team began to refer to this sentiment as Murphy`s Law. A third version of the story comes from John Glenn, who states that Murphy was a Navy educational cartoon character who was chosen as an incompetent mechanic, which led to the idea of Murphy`s Law. Murphy`s Law is by far the most popular of the humorous laws that deal with things gone wrong. There are even equations for Sods` law. The first was printed in the 70s: 1 + 1 ->2 (-> rarely means the same). But some have claimed to have invented a formula to predict when the turf law will hit.
An alternative expression, still in British culture, is “hope for the best, expect the worst”.  The list of names of the alleged phenomenon is also arbitrarily long and includes, in addition to the “laws” above: The fourth law of thermodynamics; Newton`s fourth law of motion; The reverse Midas Touch, etc, etc. Shortly thereafter (1926), Harold Wentworth listed it in the American Dialect Dictionary as “US political cant. Sod`s Law is similar, but broader than Murphy`s Law (“What can go wrong will go wrong”). For example, concepts such as “unhappiness will be adapted to the individual” and “happiness will occur despite the actions of the individual” are sometimes cited as examples of Sod`s Law in action. This would expand Sod`s Law in a general sense of “ridicule by fate.” In these aspects, it resembles certain definitions of irony, especially irony of fate. Murphy`s technological origin, as used by John Stapp during his MX981 project, is more optimistic – it was a reminder to engineers and team members to be careful and make sure everything was taken into account so as not to leave anything to chance – not the acceptance of an indifferent and uncontrollable fate. Although, according to George Nichols Murphys` account, his own use of the phrase – “If there is a way to be wrong, he will” – was closer to British usage. Since you mentioned that a Murphy who looks Irish might think differently from the word, and that I am an American Murphy who looks Irish, I had to say that I do not take offense, nor any Murphy I know. In fact, I`ve known Murphys who have a penchant for it, in a kind of “It`s my law” joke. In my opinion, anti-Irish sentiment, although it was once common, is no longer present today. Therefore, few Irish Americans would be bothered by the etymology of something like “paddywagon,” as there has been no discriminatory culture against the Irish and the United States for several generations.
www.murphys-laws.com/murphy/murphy-true.html “Sod`s Law. is the power in nature that makes it rain especially on weekends, catches the flu on vacation and rings the phone when you go to the bathroom. “There have been a number of particularly pleasant incidents. There`s the physicist who introduced me to one of my favorite laws, which he described as “Murphy`s Law or the fourth law of thermodynamics” (in fact, there were only three I heard last) that says, “If something can go wrong, it will.” It is also known as Finagle`s law of negative dynamics or Finagle consequence of Murphy`s law. (American thinker) The first printed example of “Finagle`s Law” comes from the April 1979 Indiana Gazette, although some claim it dates back to the 1940s. There is evidence that Finagle`s law, while undoubtedly influenced by Murphy`s law, is not simply the same term under a different name. Finagle`s law is more often used specifically as a parody version of the second law of thermodynamics and is given as ” The perversity of the universe tends to a maximum “. This pseudoscientific context also applies to the “Finagle constant” – a mythical mathematical constant added on one side of an equation to obtain a result when the facts do not agree with the theory. Sod`s Law, a British cultural axiom, states that “if something can go wrong, it will go wrong.” The law sometimes has a consequence: that the catastrophe will occur at the “worst time” (Finagle`s law). The term is commonly used in the United Kingdom, although in North America the term “Murphy`s Law” is more popular.  dictionary.cambridge.org/dictionary/english/sod – Once a job is botched, any attempt to fix it will only get worse.- Bread always falls upside down.- Everything that can go wrong will go wrong, and at the worst possible time in the worst possible way. The expression seems to derive, at least in part, from the colloquial language of an “unhappy sow”; A term for someone who has had a bad (unfortunate) experience, and is usually used as a sympathetic reference to the person.
 Finagle`s law follows a similar pattern.