One has no friend who has many friends.

... the friendship of worthless people has a bad effect (because they take part, unstable as they are, in worthless pursuits, and actually become bad through each other's influence). But the friendship of the good is good, and increases in goodness because of their association. They seem even to become better men by exercising their friendship and improving each other; for the traits that they admire in each other get transferred to themselves.

The man who confers a favour would rather not be repaid in the same coin.

And yet the true creator is necessity, which is the mother of invention.

The ridiculous is produced by any defect that is unattended by pain, or fatal consequences; thus, an ugly and deformed countenance does not fail to cause laughter, if it is not occasioned by pain.

Men become builders by building and lyreplayers by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.

Salt water when it turns into vapour becomes sweet, and the vapour does not form salt water when it condenses again. This I know by experiment. The same thing is true in every case of the kind: wine and all fluids that evaporate and condense back into a liquid state become water. They all are water modified by a certain admixture, the nature of which determines their flavour.