An eye can threaten like a loaded and levelled gun, or it can insult like hissing or kicking; or, in its altered mood, by beams of kindness, it can make the heart dance for joy.... One of the most wonderful things in nature is a glance of the eye; it transcends speech; it is the bodily symbol of identity. ~Ralph Waldo Emerson
It is probably a matter of temperament, and for anything I know it may be glandular.
But it is not something that can be demanded from life,
and if you are not happy you had better stop worrying about it and see
what treasures you can pluck from your own brand of unhappiness.