In this case I operate on the assumption car drivers are inherently good people. So when I am cycling in the middle of the lane (when the lane is too narrow for safe sharing), and they are behind me hitting their horn, I give them the benefit of the doubt as to whether they are being a malicious prick.
So I stop the bicycle, get off look around, check my pockets, and if their window is open I ask “did I drop something?” Because surely they would not use their horn to demand that I move to the side so they can pass me unsafely. Surely they are kindly signalling to me that my backpack is open, or that something fell from my bicycle.
Every single time, I never manage to discover that anything was lost or out of place… but I continue to give drivers the benefit of the doubt every time.
All three components of this suggestion are perfectly legal:
Take the lane to the full legal extent allowed
Wear a helmet or body cam
Carry a glass breaker and the most lethal self defense tool legally allowed in your area
My flimsy cable lock fell apart. So I needed a new lock. The common choices are a U-lock or a chain. I opted for a chain with a heavy integrated lock at one end. This chain could double as a self-defense tool. I wonder which martial art would bring the most utility to this kind of tool.
The chain is big enough that it’s partially falling out of my backpack. It could now actually be something that inspires honking on the basis that it could fall out.