Somewhat relatedly, I've contracted OK to K and expanded it from K to "potassium" in text conversations with friends, because I am a colossal nerd.
I first parsed imho as "in my honest opinion" which... isn't exactly the same? My one friend gussed the meanings of all the basic smilies from context instead of asking what they meant. This led to her reading ":P" (a teasing/funny face) as something closer to ":/" (unsure/upset? face) or "xP" (which I parse as a negative "ugh kill me now" face, but some people parse as laughing apparently? welp! Since I usually use it in a joking manner, it works out to about the same...)
i usually interpret :P specifically as teasing, and saw xP as an especially big "eff you" when telling a joke or doing a prank you know will annoy someone. like, say, you said a pun around your friend that you've told over and over so many times they essentially always react with a big "FUCK OFF NOT THIS AGAIN" you do "xP" as the response. my sister can do :/ in real life and it is just as terrifying as it is hilarious. i might try to get a picture if i can convince her to let me take one of her doing it.
Yeah, that's more or less how I interpret it in those situations too. xD Ahaha that's amazing. My friend can do :C
At some point I picked up ofc (of course) and rn (right now) from @Nochi. Thankfully I don't try to say those in verbal conversation. Also tl;dr (too long; didn't read) or "teal deer". A fun one: I was in a fandom for a while that was abbreviated TGWTG. The official fandom-wide pronunciation of that was "tig-wa-tig" Also I'm 90% sure smh is "shaking my head" but I usually read it as "so much hate". Considering some of the contexts on Tumblr there's often not much difference.
speaking of cool fandom abbreviations, i love the one for fairly oddparents, "fop" which i pronounce "foppee" for some silly reason it's a really fun acronym
yeah, SMH is 'shaking my head', sometimes it's SMDH with 'Damn' in the middle. But 'so much hate' is often accurate to the Tumblr meaning.
My friend shortens "Welcome back" to "Webas". This always throws me for a loop because I end up mentally pronouncing it similarly to "huevos" in Spanish, which is slang that can be an insult.
On a subreddit I look at from time to time you see IANAL a lot. It just means I Am Not A Lawyer but I always read it out in my head as I-anal and get a laugh out of it.
i have so many uses for all of these one seebs uses a lot: YMMV (your mileage may vary) son of the return of the revenge of SNAFU: JANFU (joint army navy fuckup; the maximum possible level of fuckup)
I see that used a lot in a slightly different sense (and also usually as tstl -- too stupid to live). It's for characters who are alive in their book because of plot armor, but the decisions they make are so stupid that in the real world, they'd be dead.
We also use it that way as well! Usually when the credits are rolling, with outraged comments of "How the fuck did [character] survive? They were totally tdtl!"
Not sure if this is on topic, but when I first saw the term cis, I tried to google or some other search engine it, and came up with next to nothing except people mocking "cissies" and the like. Was more confused than ever and still unsure if it was an acronym or what. I have a lot of trouble with acronyms though, so I'm super glad this thread exists! Btw- it may have been posted already and I just missed it and if so sorry, but what does smh mean?
I also use YMMV, although sometimes it can be confusing since most people haven't spent much time on TVTropes :P
I don't use these much anymore, but with a former friend we used to use CBA a lot, means 'can't be arsed.' He was also a european dude who stayed for long periods of time in australia and picked up some of the slang, so we would say shit like 'no wukkas' a lot.