It would merely make people uncomfortable and shrink away. It could come across as being intrusive. It may be met with aloof disdain.
Reason: There is a dichotomy in what one wants and what the people around one expects. We all expect to be polite strangers and want nothing more than to be polite strangers and sharing personal history goes again such wishes. (Or are we even expecting this?)
The disharmony deepens when what one expects from others is different from what others are willing to share.
Expecting others to be comfortably and completely honest is, on hindsight, rude. Used to think that being completely honest is a sign of respect for the other party but now, feels otherwise.
Expecting honesty doesn't respect the unique individuality and experiences of people. Perhaps one has experienced great hurt after being too open and hiding one's true feelings is the best defense mechanism? Perhaps one is just naturally shy and finds being expressive a struggle? Perhaps perhaps perhaps.
The unknown factors create such room for doubt that expecting honesty become myopic and selfish, no longer a mark of respect.
There can be no questioning: Honesty is the best policy. But, by elimination, not saying the complete truth is a close second. One must not discount the value of holding back.
A really simple issue.
If not for the fact that one must know when to be honest with one's thoughts and when not to. And when to balance on the tightrope with half-truths and white-lies. A lesson that might - most unfortunately - take a lifetime to learn.