You’ve just arrived at the restaurant and are studying the menu. Your partner/friend/relative does the same but then asks: What are you having?
I cannot say for sure I never had this behavior myself, but I certainly cannot remember the last time I asked, other than to reciprocate out of politeness (and after my choice was already made).
What I do know is that this question has always irritated me. The urge to answer “it’s none of your business” has always been strong, and yet the cause for this reaction was unclear — what is there in this question that’s not worth answering to?
In a moment of mental clarity during a recent trip, two answers came up to mind.
One is “FOMO” - the fear of missing out. Asking what another is having and study the answer - either study how the answer is delivered, and see if the other is more confident, more assertive, suggesting their choice is more socially worthy, or study the menu item itself, to see if indeed it looks more delicious, better priced, etc.
Another is laziness - the lack of desire to actually scrutinize the available choices.