The basis of insincerity is the idealized image we hold of ourselves and wish to impose on others.
Quotes
One must learn by doing the thing; though you think you know it, you have no certainty until you try.
It is a true saying, that what you fear you find.
Whenever you commend, add your reasons for doing so; it is this which distinguishes the approbation of a man of sense from the flattery of sycophants and admiration of fools.
For as children tremble and fear everything in the blind darkness, so we in the light sometimes fear what is no more to be feared than the things children in the dark hold in terror and imagine will come true.