Sometimes, acronyms are useful, but usually, they are just terrible. If you're in the military, the CIA (see what we did there?) or performing some other top-secret task, by all means, abbreviate. We can sympathize: We, too, used acronyms to notify our friends when our parents were hovering near our AIM conversations ("pos! pos!"). Otherwise, we recommend that you stop using acronyms immediately - especially these 9:
sgtm
What it means: Sounds good to me
Why it's terrible: It's basically just a positive affirmation, so a simple "OK" should suffice -- and be shorter!
Possible exception: When you're in a situation where "OK" would not suffice -- say dinner plans sound good to you, but you still need to seek approval from the rest of the group
tl;dr
What it means: Too long; didn't read
Why it's terrible: This acronym is a neat summation of why we dislike acronyms in general. Not only are you too lazy to read something that you, and presumably whoever you're conversing with, are interested in simply due to its length, but you're also too lazy to type a sentence-long excuse.
Possible exception: When referring to "Finnegan's Wake"
w/r/t
What it means: With regard to
Why it's terrible: Why is each letter in this acronym seperated by a slash? Because that's the way David Foster Wallace wrote it when he invented this acronym. If you're not David Foster Wallace, maybe consider not using this acronym.
Possible exception: When you are David Foster Wallace
rofl
What it means: Rolling on floor laughing
Why it's terrible: Because, are you? Really? You're rolling on the floor, laughing, while typing or texting? Color us incredulous.
Possible exception: When you are literally rolling on the floor laughing, because you are probably too occupied to type up a thorough explanation of what's going on
imho
What it means: In my humble opinion
Why it's terrible: We don't mind plain ol' "imo" (in my opinion), but adding in "humble" almost seems disingenuous, as if you believe your opinion to be a significant one. This passive-aggressive statement is the acronym equivalent to "No offense, but ...".
Possible exception: When you're using the term sarcastically
fml
What it means: F*** my life
Why it's terrible: The problem with this acronym is the context in which it's typically used. Usually, "fml" is not used to describe genuinely bad situations, but minor inconveniences, like staining a shirt you kind of like at lunch.
Possible exception: When you're referring to something a little more terrible than, say, a romantic interest not texting you back
icymi
What it means: In case you missed it
Why it's terrible: This is often used for news articles that are reposted, and sure, there is a lot of information floating around, so there's no harm in bumping interesting stories. But if your audience and/or friends missed it the first time, they'll likely miss it again because they'll be so confused by this esoteric acronym.
Possible exception: When your tweet is too long to include the entire, spelled-out phrase
wfh
What it means: Working from home
Why it's terrible: So, what you're telling us is, you're in your pajamas, sipping coffee out of your favorite mug, and you can't spare the extra two seconds it takes to explain that you're "working from home"? This must be the laziest acronym of them all.
Possible exception: When you're working from home because you have some sort of personal crisis going on, and you are genuinely frazzled.
ftw
What it means: For the win
Why it's terrible: Regardless of its origin, this acronym has come to mean "I enjoy the thing I'm describing," as in "grammatical correctness ftw!" or "coffee ftw!" It's even worse than saying that you "heart" something.
Possible exception: Not applicable
When someone uses some out-there acronym that you've never heard of, here's one that's ok for you to use: YJMTU, which means: "You just made that up."