Bethberry - I don't think it's meant to be particularly rude, it's a word that my mother uses quite often and she
hates swearing. In fact she told a young bloke off for swearing the other day and called him an "arrogant s**" when he dared to argue back.
You might use the two words if say, you dropped your toast buttered side down, which in turn leads to the harmless phrase "S**'s Law", i.e. "Murphy's Law". It would have been a highly impolite word to use when Tolkien was alive, but these days, it's nothing much.
*s used so as not to offend if it's a bad word for some.