I recently found a lot of my friends were using "over" with an adjective describing their well-being/how they felt, e.g. "I'm sad over something/somebody" which in my opinion sounds somewhat off(?). As far as I'm concerned "about" would sound a lot more accurate.
I tried to find some difference between them and the only one I could find till now was that over appears to be used more often when the state of being relates to a person ("sad over someone"). However, I also found that "sad over a breakup" is used quite often as well (which isn't a person since it's "something"). Accordingly, I'm not entirely sure which one is right or rather sounds better.
Moreover, I'm wondering if this construction works with other adjectives like "sad", too, as in "I'm happy/relieved/etc. over something/someone".
Best Answer
This is likely related to the much more common phrase crying over a person or thing. Different emotional gerunds seem to take different prepositions in common parlance, e.g.
These are all actions you take when feeling some emotion at another person or thing, though despite their seeming transitive nature they are usually intransitive. Note that even when "at" is used, it does not mean you are literally doing this in front of them (contrast with "snarling at you", which requires one to be present and snarling in person).
It seems quite likely that "crying over" a thing led to being "sad over" it. This is probably why other adjectives don't seem to fit: you don't "laugh over" someone, so being happy over them doesn't seem to fit either.
Now, as to why we have different prepositions for different actions, I wouldn't dare to even venture a guess.