Hi anxiety!
http://www.guardian.co.uk/Columnists/Column/0,,1653990,00.html
It appears to me that Lucy go off lightly, obviously because she had no elder brothers or sisters or, to give them their full title - socially sanctioned sadists.
For instance, I used to know two sisters who shared a room and, at lights out, one would say to the other (actually the younger to the older, but this is the exception that proves the rule) 'there's a murderer under the bed'. Modern houses, I am sad to report, do not have much in the way of noise insulation and the resulting terrified screams curdled milk for miles around.
I suppose that children have irrational fears because much of the world seems irrational and so their irrational fears are just as real as any rational ones. As you grow up, sprouting hair, flab and acne these fears grow up too, turning from fears to dread and then, worse still, mild concern.
For instance, I work five minutes from the House of Commons or, as it's knows these days, the terrorist target of choice, but am I worried? No, I'm too busy thinking about bacon sandwiches, iPods, foreign travel, and, in the dread category, that nagging pain in my elbow that may be muscular stiffness but could be a hybrid of early onset ebola and a Victorian wasting disease.
Basically, people divide into two different social groups. People who worry (about their loved ones, about the future, about last night, about testicular cancer, about getting fat, about getting old, about the amount of hair in their ears) and psychopaths. That, though, is why we have alcohol. It's nature's prozac.