Michael Byrne contemplates shyness:
Some 15 to 20 percent of humans are born shy, which roughly parallels the incidence of shyness or anxiety or whatever you chose to call it within different species of animals. Shyness is an evolutionary tactic. Someone within a society must be shy for that society to be selected for and survive. If every member of a population was gregarious and stoked to rush into vulnerable positions, that would be a population less likely to persist. In other words, it’s natural and neccessary for species to have shy members. Humans aren’t an exception. Some of us are just like this, and that’s for the good of the species, no matter how aggresively we try to medicate it away.
Bryne, who is shy himself, isn't happy about this:
[B]eing shy, or having "social phobia," sucks. It feels bad. It limits opporitunities, by definition, to experience pleasure. This is why there’s a massive market for SSRI treatment for SAD and social phobia — Pfizer isn’t marketing into a void or inventing experiences. And this is why it gets really frustrating when armchair experts start going on about how it’s all the drug companies making up new diagnosis for "normal" feelings. Feeling terrible and excluded — thinking here of that solitary elk lurking on well-trampled pee-snow under the same evergreen branches hiding from hunters — may be normal, but often, it’s also terrible. Shouldering the persistence of a species or not, no one wants to feel that way.