Typical folks cutting in front of me while I am barely at safe breaking distance from the car in front of me, on speeds > 100kmh. This is of course always in at least semi-dense traffic, and them immediately obscuring view further means I have less than second to react to any stronger breaking or I slam into them.

I honk them, then they often get aggressive that I dared to react to their perfectly cool maneuver that gave them those precious extra 5 seconds. Bloody a-holes. Had few almost-collisions even this year due to too aggressive drivers riding too close, some were literally car in front of us or next one behind. Keep your distance, I can't emphasize this enough.

Have you considered buying a dashcam? Then in case you do actually hit them because you weren't able to break fast enough, it's very likely that insurance will end up siding with you, as opposed to the usual outcome where you're the rear-ender.

No but that seems like a good idea, thank you.

My hand gesture for "Hey did you hear about the inverse Pascal Scam? It suggests that low-probability high-impact risks are easy to ignore, and I think that's what you're doing right now and that's not going to be good for your health, or mine for that matter, so maybe think about that a bit more in the future" is to raise my middle finger. Unfortunately it inevitably makes the situation worse somehow.

I’ve switched to a thumbs down in traffic and can’t recommend it enough. Let’s then know how they should feel without escalating like a middle finger.

I have switched to smiling at things people do well in traffic and trying to give positive reinforcement when I see people who care about others. Some even do it in ways that might seem stupid, e.g a guy in the wrong side of the street was actually just being very considerate.

Nice! I tried thumbs up (ie sarcasm) but that's snarky too, and somehow never realized that you could actually do the same thing non-sarcastically. Srsly wow :-) Gonna try, thanks