It's complicated precisely because it's signalling, so in context insecurity over the size of the diamond might not be an actual red flag. You might decide to take a principled stand on the matter, and I agree that insistence on a large diamond is a deal breaker, but not everyone has the same upbringing, cultural belief system, or social environment.
There's a whole variety of reasons why that might happen. Societal expectations, economic reasons, insecurity, etc.
People are generally obsessed with status symbols, jewelry isn't really any worse than anything else.
You know plenty of people don't do any of this stuff, right? I get the feeling you meant that to be a broad list that would have virtually everybody covered in one respect or another, but if that was your intention you failed.
I do think people who are not particularly interested in status signaling are somewhat rare.
https://www.scientificamerican.com/article/the-psychology-of...
>...apart from economic payoffs, social status seems to be the most important incentive and motivating force of social behavior.” The more noticeable status disparities are, the more concerned with status people become, and the differences between the haves and have-nots have been extremely pronounced during the economic recession of recent years.
Talk about a book you read? Talk about how a certain restaurant is terrible? Talk about where you went on vacation? Talk about your job? Talk about music you like?
All those things signal status.