Old friends become bitter ...

Old friends become bitter enemies on a sudden for toys and small offenses.
 Robert Burton

Quotes from the same author

A dwarf standing on the shoulders of a giant may see farther than a giant himself.
 Robert Burton
Worldly wealth is the Devil's bait; and those whose minds feed upon riches recede, in general, from real happiness, in proportion as their stores increase, as the moon, when she is fullest, is farthest from the sun.
 Robert Burton