Horns should be used to convey one short message: “pay attention”.
That’s it. Not “you were wrong” or “i hate you” or “i’m frustrated” or “i want you to move”. All those do are confuse, frustrate, and anger other drivers. I know better but I am still guilty of doing it on rare occasions, usually when someone has just used their vehicle as a weapon and tried to hit me or threaten me.