And most of us are not militant in-your-face egotists; we might have some appreciation of our talents or strengths, but in general, we are very much aware that there are others who can run rings around us in any department we care to name.
As long as this gives us a healthy attitude of humility, things are fine. But what seems to happen is much worse...the person seems to feel that s/he is not interesting/intelligent/whatever to "match up" with others...and tends to retire into a shell from which it is difficult to extricate hem. All the more, this person *appears* boring when s/he is NOT.
This feels even worse, to me, when I see others, far less deserving of the spotlight, hog it with great glee, while the people who probably know more about the subject stay in the background because of several reasons: a natural disinclination to push themselves forward, a feeling that probably the other person IS better than they are, and sometimes, the feeling that they don't really care! (This last instance doesn't apply to my present peroration, as they are the people, in Isaac Asimov's words, who are "so intelligent (substitute interesting or good-looking or rich or whatever) that they see no need to advertise the fact." They are happy in themselves.)
We then have the amusing spectacle of the less-knowledgeable holding forth in style to an audience of people comprising those who actually know MORE than the speaker! (this could be a speech or a meeting of people, or whatever.)
I find Indian women particularly prone to this complaint; they have, traditionally, a lifetime of being casually considered second-grade persons, to the point where they take on the attitude automatically.
When I was teaching music, I found that with women, most often it was not so much a matter of teaching them to sing, as of boosting their self-esteem to the point where they thought that they *deserved* the one hour of the music class as time devoted to themselves, and also, to the point where they would open their throats and sing uninhibitedly. "What will the others say or think?" seems to be the guiding force of SO much inhibition and self-repression that I see around me.
It took me, too, a long time to throw out (not always successfully, alas) the "I'm not worth it" attitude that I grew up with. All my life, I was compared with a cousin who was studying to be a doctor. "You are studying ENGLISH and PHILOSOPHY! Of what use is that?" was often openly asked. It was only later that the term "liberal arts education" came into use. Until then, I could not convey to others that I was thoroughly *enjoying* my studies (that was also a no-no..one was supposed to study HARD and STRUGGLE and SUFFER to do well academically!)....and when I first met KM's IIM-A group, I had this big chip of "I'm only a lowly housewife" on my shoulder...but lo and behold, I find that those who are comfortable in their own skins, have NO problem in appreciating things about others. My singing... and even my lousy jokes were appreciated..and I really do think I grew up as a person then, and I too have learnt to look for what is interesting in a person without discarding hem too easily. And...there is always SOMETHING that is interesting about each person I meet!
Self-esteem (not to be confused with mock modesty or veiled arrogance!) is a very necessary part of one's personal happiness. I've been very, very lucky to be able to get some measure of it (though it still fails me occasionally, when I quail at meeting a new group)...and I wish everyone I know gets enough of it, too....