Sharing a part of yourself.... Should you?

Now I'm a reserved person, you don't really need to be exceptionally perceptive to know that.. I respect the life and privacy of others and never intrude.. Is it really that tough for other people to do the same? Right now it doesn't seem so bad, so far so good right?
what about later?
why do i need to share personal things with anyone? why is being a social recluse a bad thing? is it because society as a whole is scared of people that they cannot keep tabs on? people with the need for personal space are treated like bad apples..
so what if i don't want to come for your religious laced social gathering, why am i any less of a human being because of it?
in a marriage, it is considered, well, bad isn't the ideal word here, so I'll say, not desirable, to keep 'secrets' from your 'better?' half.. why is that? does being married rob you of your personality? Of late an increasing number of married (and also people generally in relationships) people have begun question their partners about seemingly trivial things.. where are you going? why are you going there? what will you do there? A sense of trust that seem to exist in relationships a couple of generations back seems to be fast vanishing into a cloud of mistrust and suspicion.
A common factor that results in a couple visiting a marriage counselor is "he/she wont share her feelings with me"
What IS this need to completely 'know' someone! you do realize that you'll never really 'know/understand' anyone.. i can attribute the shock of the failed relationship to the grieving partner once thinking they had fully understood their significant other. "he cheated on me! *sob and i thought i knew him!"
Really!! are the majority of you nervous because you don't get along with yourself? is that why loners are subjected to harsh stares at restaurants when they attempt to have a quiet peaceful meal by themselves? or why a single person in a concert/theater is given a look of pity/sympathy as if to denote that he was stood up by someone?
modern science is gradually, with all its technology creating the perfect world where everyone is slanting towards being a little dissocial.. at the same time, it is constantly categorizing us into new mental diseases that seems bent on convincing us that we're all a little less that your average societal alpha man.. we're grouped into mental illness like the one mentioned above "http://en.wikipedia.org/wiki/Antisocial_personality_disorder#Diagnostic_criteria_.28ICD-10.29_-_dissocial_personality_disorder.E2.80.8E" and we're told that one in five people have a mental illness of the like..

its sad that when most people don't even get along with themselves and cant even spend a day with only themselves for company, they strangely expect you to do so..