Words can't be taken back

When you ask someone about the qualities they appreciate in another person, you'll probably hear sincerity a lot. And that's just great, we all want sincere friends, partners, colleagues in our lives. But let me ask you something... Should there be a limit? When do you draw a line? What if you hurt someone beyond repair with your sincerity? Hmm. What if you mistook selfishness for sincerity...?