According to a 2016 study followed up with newly published research by Binghamton University, you're right to feel like you've done something terribly wrong whenever a friend responds to your text with accurate punctuation.
Scientifically, there's nothing more passive aggressive than a period (unless you're too old to get it, then you're exempt).
In the abstract for the study, the professors explain that "the inclusion of a period after a positive one-word response (e.g., yeah.) led readers to perceive the response as less sincere."
Because why in the world would you ever need to officially end your one-word sentence with punctuation? You're not being thorough, you're being petty. You're absolutely furious that your friend is running late and you want to ruin their day with a quick and effective dot.
Case in point (pun intended):
In formal writing, such as what you'd find in a novel or an essay, the period is almost always used grammatically to indicate that a sentence is complete.
With texts, we found that the period can also be used rhetorically to add meaning.
Specifically, when one texter asked a question (e.g., I got a new dog. Wanna come over?), and it was answered with a single word (e.g., yeah), readers understood the response somewhat differently depending if it ended with a period (yeah.) or did not end with a period (yeah).
This was true if the response was positive (yeah, yup), negative (nope, nah) or more ambiguous (maybe, alright).
We concluded that although periods no doubt can serve a grammatical function in texts just as they can with more formal writing -- for example, when a period is at the end of a sentence -- periods can also serve as 'textisms', changing the meaning of the text.
Besides the passive aggressive period, the new research determined something else you already know: that using "emoticons, irregular spellings (sooooo) and irregular use of punctuation (!!!)" can add and change meaning to make a message feel more positive. Those types of creative grammar nuances stand in for the "tone of voice and pauses" that we use in face-to-face conversation.
Sorry, that was rude. TBH, this study is suuuuper validating.