I'm currently reading a story where the author frequently uses abbreviations where the meanings he uses them for are used only in the USA, and some even have another meaning elsewhere. The normal thing in written documents is to have the full meaning with something the first time you use it as an abbreviation or acronym or slang, so people will know what it is when they see it later. There's a few in International language where they're known the world over, but not many - BTW (by the way) is one International abbreviation that comes immediately to mind.
What caused the rant was in the story the author refers to USA states with only two letters, and it hit a nerve when I totally lost the plot trying to work out where he was talking about Ks and MO in the same sentence. A reader shouldn't have to have an intimate knowledge of USA Abbreviations or have to go digging through Google or Wikipedia searches to work out something that simple because the author is too damn lazy to write the full state name.
I'm sure some people will say it's obvious what they are, but can you honestly say a system that uses the first two letters for some names, the initials for some others, the first and last for still more has them all as obvious. Then there's the alternate abbreviations shown on the Wikipedia list at
Like Kansas can be abbreviated as - KS, KA, Kan, Kans, Ks, Ka. North Dakota = ND, D.Dak, N.D., NoDak.
I only mention the states because it threw me out of the story to work out what the hell he was talking about. Then I only managed it because the military base mentioned had its own Wikipedia page.
Please think of your readers and tell them what the abbreviations, acronyms, and slang mean.