Frances Willard, leader of the Women’s Christian Temperance Union and crusader against inebriation was speaking about herself learning to ride a bike as well as her injuries due to the learning process.
It let me out into a new world, greater, more mellow, more god-like, and it did me no harm at all.
Robert Hurst deals with the dangers of cycling in his book "The Bicyclist's Manifesto,"
The same feature that leads to a glorious sense of flight when everything is going well also causes the occasional topple when trouble arises… Those who really love to ride don’t like that fact about bicycling, but they won’t denounce the trade-off. They know there is no other way. Freedom, as they say, is not free… Bicycling demands coordination, fluidity of motion, and quickness of reflexes far beyond what is necessary for driving.
He goes on to list some of the things bicyclists must consider.
Bicyclists must contend with a large number of factors that drivers don’t need to consider, in particular many different types of road damage, debris, and surface anomalies. You can smack into a little pothole when you’re not ready for it and crash. Go around a corner too fast and wipe out on some sand. Wet railroad tracks become treacherous obstacles. Seemingly tiny cracks can displace the front wheel.
I would add to the list front wheels falling off randomly. When I was in college, I was riding down a bike trail and my front wheel just decided it didn't want to hang around anymore. My front fork dug into the asphalt and flipped me headfirst into the unforgiving pavement. I woke up in the ambulance some time later and spent some time in the hospital for trauma to the head. I broke my helmet in half and skinned myself pretty good. After a few weeks, I was fully recuperated and amazingly I still ride the same bike today with the same mutinous wheel (however, I do have a new front fork).
Lesson learned: Tighten the heck out of your quick releases for your wheels and check them often.
The truth of the matter is that there are dangers all throughout this life and if you put yourself in a bubble so you can feel safe, life isn't really worth living. Hurst says,
It is an undeniable truth that the bicyclist is more vulnerable to injury than the driver, but it is not reasonable to be paranoid about bicycling in traffic and then to climb into an auto without a second thought.