Are you quiet? Play your cards very close to your vest if you decide to play? Keep your own counsel. Tell no one what you REALLY think? Why?

Most of the time I am quiet. But the people I know, know exactly where I stand on issues.

Discretion and humility.  Also being realistic - few people care what I think.  Going on constantly about what I think only makes me unpleasant, presumptuous, and intrusive.  And something of a bore.