We all have known people who blur gender expression but not all feel that their identity is in complete conflict with their birth sex. It is only when the core gender identity is felt by the individual to be in direct opposition to birth sex that the person will typically seek a corrective measure. The combination of these three factors makes it that we are clearly dealing with a kind of continuum.
Here are some examples we all know:
• Drag queens are male and identify mostly as male but use exaggerated forms of female expression
• Butch lesbians are female yet identify strongly with maleness and express it without needing to resort to transition
• Crossdressers identify as male but express themselves as females on occasion.
• Androgynous or gender queer people can identify as one gender or both and express as one or both in a varying combinations.
The interplay between these three components varies individual to individual which contributes to one’s uniqueness. Additionally, the degree to which one willing to brave society's disapproval is also an important element. Given the tendency of people to not want to be rejected, what we see out there is actually the tip of a submerged iceberg which historically did not give an accurate picture of some people’s natural tendencies.
As a result people who tried hard to meet expectation(and I count myself among them)suffered in silence.