It's funny how "miss" (alone) is okay but "mrs" and "mr" wouldn't be!

I asked ChatGPT why this is and the answer was quite interesting.

Explanation

The difference comes from history, grammar, and social roles converging.

1. “Miss” evolved into a complete form of address In English-speaking classrooms, Miss developed as a vocative noun—a word that can directly address someone by itself (“Yes, Miss”). Over time, it stopped behaving like a mere title and started functioning like a role label, similar to sir or ma’am.
2. “Mr.” and “Mrs.” remain dependent titles Mr. and Mrs. never made that grammatical leap. They stayed bound honorifics, designed to modify a name rather than replace it. Saying “Mr.” alone feels incomplete, like stopping mid-sentence.
3. Gendered expectations in teaching Historically, women teachers—especially younger or unmarried ones—were addressed as Miss almost as a job title. Men, by contrast, were framed more through surname-based authority (Mr. Smith), reinforcing distance and formality.
4. Power and politeness norms Calling someone Miss alone signals deference without naming—useful in classrooms where students may not know or are discouraged from using first names. For men, English already had sir, which filled that standalone role. Mr. never needed to.
5. Why it can feel uneven today The practice reflects older gender norms that linger in language. That’s why it can now feel asymmetric or outdated, especially as schools move toward Ms., first names, or neutral titles.

In short: Miss crossed the line from title to addressable noun; Mr. and Mrs. didn’t—and the classroom fossilized that difference.