"People in disagreement are not necessarily unhappy at all."'

Sorry! Tears are usually a characteristic sign of sadness, unhappiness, of gloominess: Looking "with tears ... in the rearview mirror." I guess in this case, however, the tears are "of disappointment," which disappointment can be hopeful,  a nurse of wisdom, as it were. Of course, there'll always be disputing about peoples' tears. And then there is grief and sorrow without any tears.