It's the explicit inclusion of period where 'normally' there wouldn't be one. In texting or DMs it would normally be assumed that one-liners wouldn't contain punctuation except to enhance effect, so the inclusion of the full stop is being read as a 😐 or exaggerated neutrality

What about it makes it look passive aggressive?

Good question!

As I explained later in the post, “Great.” looks like sarcasm. My brain interprets it as having a sarcastic tone, and thus being passive aggressive.

(I am not alone in this, hence the very thing we’re commenting on.)

How would excluding punctuation make it not look passive aggressive?

You might as well ask why tone of voice changes the way we interpret things. Written short-form communication has evolved cultural norms that some people understand better than others, just like spoken communication. Chalk my tone interpretation up to an adolescence spent on IRC.

My point is that the full stop being passive aggressive is contextual. None of my uses of it here are intended to portray passive aggression or sarcasm, and if I wanted to do that I would not only change my sentence length and structure, but also my vocabulary.

But of course these norms aren’t as readily understood as actual tone of voice, which is why things like “/s” can be useful.

In my mind, the full stop "sounds" like dropping the voice at the end, like you do at the end of a sentence.
And in speech, dropping the voice at the end of "Great" would sound sarcastic.

Whereas an exclamation mark "sounds" high-pitched and excited.

And no punctuation is so normal in text that my mind "adds" the expected sign at the end, which after "Great" would be an exclamation mark.

It's really hard to explain, I hope I'm making sense.

Wow. What a good question.

That's silly

I don’t know what to tell you, communication is complicated. A lot of this is subconscious.

and at the very least probably gonna cause unconscious bias to second language speakers, neurodivergent people & just anyone who doesn't communicate via text as much as we do

I agree, which is why it’s important for us to understand context and to attempt to interpret what the other person says in the best light.

I didn’t think my dad was actually being sarcastic when he replied that way. His text conveyed a tone he didn’t intend, just like when my neurodivergent ass says something in a tone of voice harsher than I intend.

This is no different from spoken communication, except there we get additional clues about neurodivergence and/or linguistic familiarity.

If he does it when he is excited you might let him know about exclamation marks.

Maybe he is trying to be sarcastic.

The different context means it's not a literary communication, but notation for casual speech.

More script or score than Strunk and White.

In that mode, punctuation is performative, and with a period after one word you should weigh heavily on a grim tone of voice, or perhaps sarcasm.

As an old fart and former editor, context is key: there are many modes of expression, and the rules vary.

It simply is correct grammar, something kids seem to be unaware of nowadays.

What a boomer take. I could just as well say that the "kids" seem to be more aware of the use of punctuation in text messaging and the implied emotion they convey

Everyone in this thread that can’t understand how a period can be passive aggressive just reminds me of Sheldon from Big Bang Theory. They are so focused on what the rules strictly mean, that they can’t detect the nuance of how people actually communicate.

I’m not saying that’s the interpretation I walked away with. Context is important. I knew my dad wasn’t being sarcastic, just read that way. It made me laugh, it made my wife laugh!

It’s like back when some people didn’t realize all caps meant yelling and they would go around with caps lock on until they had it explained to them.