Misunderstanding
Overview
A misunderstanding is a state where the intent of the person sending a message and the interpretation of the person receiving it don't match. In face-to-face communication, nonverbal information like facial expressions, tone of voice, gestures, and timing helps get the meaning across on top of the content of the words. In psychologist Albert Mehrabian's experiments, when people received messages about feelings or attitudes in which the words contradicted the voice or facial expression, verbal information is said to have made up 7% of the cues they relied on. Keep in mind that this number is an experimental result limited to "situations where words and attitude contradict each other" and isn't a ratio for communication as a whole, but it can be read as showing that nonverbal information plays a part in carrying the nuance of feelings.
In text communication, this nonverbal information is lost. Only the words are left. One of the reasons question box exchanges easily lead to misunderstandings is this lack of information.
Why question boxes breed misunderstandings
Question boxes have 3 structural factors that amplify misunderstandings. The first is anonymity. Since you can't picture who sent the question, all you can do as the receiver is guess at its intent. The same question, "Do you have a boyfriend?", feels like light small talk from a close friend but like prying from a stranger. When it's anonymous, this call is hard to make.
The second is the lack of context. Questions sometimes arrive suddenly, with no conversation before or after. You end up reading them without the background: you don't know why they asked or how they felt when they sent it. The third is negativity bias. It's the way people react more strongly to negative information than to positive information, and even a short, unclear reply can get read negatively. A single "Hmm" sounds like a casual response face to face, but in text it feels cold.
Ways to reduce misunderstandings
You can't get rid of misunderstandings completely, but you can work to reduce them. On the sender's side, add a few words about your intent to the question, like "I'm just genuinely curious, but..." or "I don't mean this in a bad way." A line like this gives the person answering a clue for interpreting it.
On the side of the person answering, a habit of choosing a charitable interpretation when the intent of a question is unclear also helps. If a question could be read as either malicious or well-meaning, assume it's well-meaning and answer. Even if it turns out to be malicious, an answer written on the assumption of good intent also helps leave a good impression on readers. Taking on the risk of misunderstanding is the role of the person answering, and the mood of the question box changes depending on how they take it on.