Sincerity and goodness ought to have their own unmistakable odour, so that one who encounters this becomes straightway aware of it despite himself.  A candour affected is a dagger concealed.  The feigned friendship of the wolf is the most contemptible of all, and to be shunned beyond everything.  A man who is truly good and sincere and well-meaning will show it by his looks, and no one can fail to see it.

Marcus Aurelius (AD 120 – 180), Meditations