The good people of 4chan /b/ have been diligently collecting the more graphic examples of mistakes people have made. While ostensibly for lulz, documented mistakes can provide us with valuable information about the world around us.
In attempting to categorize the evidence, mistakes seem to break down into two major categories: expected and unexpected.
Skaters know that this happens all the time and that risk seems illusory: Concentrating on the apparent risk means you can screw up elsewhere.
Counter-intuitively, sometimes the run-up or run-down to a trick seems to be the riskiest part.
Likewise, bull fighters face the same issues. They step into the ring knowing that either they will destroy a bull, or the bull will destroy them.
Since the people involved expect these futures, it seems difficult to call them mistakes. They took their chances and things just turned out poorly.
When is it, then, that truly Unexpected things occur?
For children, the world has a seemingly unending supply of Unexpected.
With a drastically limited amount of attention and experience, they often pay attention to the wrong thing.
Even when paying attention to the right thing, children just try things and generally seem to trust that what they're doing won't be problematic.
* Note that watching and recording seem quite different. The act of recording appears to turn one's brain off.
Children trust that consequences won't last for the rest of their lives.
By adulthood, though, we expect people to be aware of their surroundings and to have a fairly good notion of their actions' impact.
So why do we keep making mistakes?
They appear to be caused primarily by:
Given a gesture of help or some communication, we can fall into the trap of assuming that we have sync'd on all the relevant details.
We have lots of coordination systems: from something as simple as "on 3. 1, 2, 3!".
And they do, for the most part.
Despite much evidence to the contrary.
Or that they'll be able to get out of the way in time.
The problem is that cars have the element of surprise and can be quite quick.
And we don't have much experience with those relative speed differentials.
* Note that moving to the side by a meter was the key difference.
Many critical systems can fail quite abruptly, such as a braking system.
* Most braking systems fail incorrectly in that they fail "open" so drivers end up with no brakes. They should fail "closed"; however, that's another engineering trade-off of cost vs benefit.
However, we don't seem to have an innate understanding of how the other forces are changing.
Even as an adult, we may be lacking critical knowledge.
We may be aware of the power needed to run a train. And not aware that the wires above the train actually power the train.
* We also seem to differ across time and situations in our abilities to apply knowledge. See the rather large wikipedia list of cognitive biases
We may not know that crocodiles can lunge and are native to an area. Preoccupied with the present danger of a bungee cord failing, we fail to verify that the landing site is safe.
* Note that this video is fake, just like every one of the previous videos.
Be aware of the forces around us.
Yes. Now as they say in /b/, GTFO.