In places where traffic lanes are treated as suggestions, it makes sense that people use their horns to make other drivers aware of where they are. This form of echo location offers a semblance of order to an otherwise chaotic situation, preventing near accidents. In contrast, on typically quiet roads, the horn is reserved for moments of exasperation and the occasional catcall.
I wish there were a way to distinguish between these types of beeps, possibly by varying their pitch, tenor, or volume. Adding a new dimension would help alleviate miscommunication that can unfortunately result in road rage. But, I imagine that it'd suffer a similar fate as irony punctuation, that's intended to prevent misunderstandings from written sarcasm. While this solution may technically solve the problem, it's unlikely to see any meaningful adoption since cultural attitudes are already deeply ingrained.