Any general statement is like a check drawn on a bank. Its value depends on what is there to meet it.
What thou lov'st well is thy true heritage.
As a bathtub lined with white porcelain, When the hot water gives out or goes tepid, So is the slow cooling of our chivalrous passion, O my much praised but-not-altogether-satisfactory lady.
Every great change is simple.
Genius... is the capacity to see ten things where the ordinary man sees one.
In verse one can take any damn constant one likes, one can alliterate, or assone, or rhyme, or quant, or smack, only one MUST leave the other elements irregular.