I've always wanted two horns in my car: one that toots with a smile and a tip of the hat, and one that heralds your pending demise. It sounds like Australia cycle bell culture does that with short vs. long bell ding-a-lings.

Which is kind of how it has worked with cars, except I find that more and more cars have a style of horn that's hard to control with the necessary precision. Maybe this is Canadian culture but I get very anxious that my horn will honk for a millisecond too long and the poor victim will think I'm angry at them.

I can corroborate this finding -- I think the horn switch is just a logic-level digital switch going into one or more MCUs somewhere, subjected to all manner of latency and (probably) CANBUS jitter. It's not great. Trying to send Morse, or even a quick 'toot toot' results in a garbled mangled mess, and I find that very annoying. My early cars & motorbike had what felt like direct, switched control over power to the horn, those were great to use. I've debated installing a dedicated pushbutton rated for the amperage or at least controlling a solenoid somewhere that would power the horn.

As an experiment, I've found that you can reliably detect the presence of crummy horn control by trying to pulse the horn for the shortest amount of time possible. The shorter my push on the horn button gets, the more likely it is that the timing will feel wrong somehow, or the horn doesn't even sound at all.

I've definitely tried friendly beeps at friends or neighbors and it came out sounding like an angry honk.

The Ineos Grenadier 4x4 has a 'toot' function for cyclists, largely because Ineos is a sponsor of a cycling team.

https://m.youtube.com/watch?v=PbGp24MIRDQ

Some large trucks have that. A "city horn" that is like a normal car horn, and the traditional air horn that will rattle your windows.

go somewhere appropriate and do a little practice with the friendly multi-tap vs. the two-hand push!

adding on a wave helps too; I wish more drivers waved...