Grumpy Baby-boomers will oft have cause to make exclamations like this (but they may phrase it in less polite language). Or they may have no cause at all, but exclaim anyway.
One thing that is sure to raise the ire of older professionals is casual language in e-mails.
On this point, the Boomers are not wrong: and certainly the very casual style of the text message has no place in professional correspondence, even when it’s digital. Srsly.
That said, at least two of the abbreviations beloved of texting millennials have an older provenance than you might imagine.
IDK, short for ‘I don’t know’, turns out to be US military slang from the First World War. The News Courier of Athens, Alabama reported on 17 August 1918 that IDK was ‘the latest American soldier slang … which stands for “I don’t know” in reply to fool questions asked by recruits and men who have just been landed.’ Or perhaps by partners in law firms.
OMG (‘Oh, my God/gosh!’) is of roughly the same vintage, having been used by Admiral Lord Fisher in a letter to Winston Churchill (then Minister of Munitions) on 9 September 1917. While the admiral explained that it stood for ‘Oh! My God!’, he was using it as a short form for a fanciful new order of knighthood, jokingly modelled on the existing Order of St Michael and St George (the grades of which are abbreviated CMG, KCMG and GCMG). So, not quite how the kids are using it now.
Even if IDK and OMG pre-date the Boomers by a long way, you still shouldn’t use them (or WTF, LMAO, LOL and the like) in your business e-mail.