Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

(1) I suggest that you avoid heels where there are marble floors, don't lean out of the shower, avoid running on wet steps etc etc.

Or I could move into a padded cell with no sharp objects, breathe and eat liquidised food in case I choke. I mean, if there's even a tiny risk it's just not worth it, right?

Come on, life includes risk. Adults manage them sensibly. The question is not just "what if the worst happened?". A rational decision should consider the whole range of outcomes, the likelihood of them happening, the cost of reducing the risk, the cost of not doing an activity at all and the benefits of doing it. Most importantly of all, it includes recognising that everyones, including your own, "common sense" about things they are not an expert in is going to be flawed, and therefore considering evidence, research and expert opinion even if it contradicts your knee jerk assumptions or "what everyone knows".

In other words, a "rational" decision for the real world cannot be made by reducing the world to simple black and white.

(2) "riding a more aggressive / faster bike" - that makes you sound quite unrepresentative. My experience of this site and cycling in London would suggest that a fair proportion of cyclists spend their lives on aggressive / fast bikes and trying to get where they are going as fast as possible as a matter of principle. Should these people be wearing a helmet in your opinion (would you recommend that they do - obviously you would not tell them to)?

No, they should stop being dicks and ride like grown ups. If they decide they want to be dicks because it's more fun a helmet might make a trivial difference, but frankly I'd rather they didn't wear it because as I said a great many posts ago, putting a helmet on top of bad cycling creates a misleading picture of what is safe cycling which leads inexperienced cyclists into dangerous practices, and I care far about about the safety of people who want to be safe than people who want to ride like dicks.

Is your priority for dealing with dangerous drivers to make sure they have airbags?