Non-verbal communication
Overview
Non-verbal communication is a general term for the ways we convey information and feelings without using words. It includes facial expressions, eye contact, tone of voice, gestures, posture, and the physical distance between people. In experiments that Albert Mehrabian summarized in a 1971 book, when words contradicted voice or facial expression about feelings or attitudes, listeners were reported to judge the other person's attitude 7% from the words, 38% from tone of voice, and 55% from facial expression (Mehrabian's rule). This 7-38-55 ratio is an experimental result limited to "situations where words and attitude contradict each other," and Mehrabian himself rejected generalizations like "93% of all conversation is non-verbal."
The non-verbal information that disappears in text
Everything exchanged in a question box happens in text. That means the non-verbal information that helps carry emotional nuance face to face is lost entirely.
The short word "nice" (iine, just three characters in Japanese) means agreement if you say it with a smile, indifference if you say it with a blank face, and disapproval if you say it in a sarcastic tone. But a written "nice" doesn't tell you which tone to read it in. Readers can only interpret it according to their own mood.
This is one of the main causes of misunderstandings in question boxes. Behind the gap between what the writer means and how the reader takes it lies the missing non-verbal information.
Ways to make up for non-verbal cues in text
Even in text, there are ways to partly make up for non-verbal information. Emoji and kaomoji (faces made from text characters) can stand in for facial expressions. How you use "!" and "?" can convey tone. "(warai)" (laughing) and "w" work as signs that you're joking.
However, these are only substitutes and aren't as precise as face-to-face non-verbal information. That's exactly why, in text, it's important to keep in mind "write so it gets across" rather than "it'll probably get across." Avoid vague expressions and put what you mean clearly into words. Since you can't rely on non-verbal cues, you make your words more precise instead.