Proverbs 14:10 (NKJV) — 10 The heart knows its own bitterness, and a stranger does not share its joy.
Private emotions. Neither the joys nor the sorrows of one person can be wholly shared with another. No person stands in such an intimate relationship with another as to identify perfectly with what that person feels. Nevertheless, Christians should attempt as far as possible to identify with others in their sorrows and joys.
Romans 12:15 (NKJV) — 15 Rejoice with those who rejoice, and weep with those who weep.