The first rule of quality is that it must be defined.
Do not be avaricious； do not be a recluse.
The greatest problem for mathematicians now is probably the Riemann Hypothesis.
The walls of the educational system must come down. Education should not be a privilege, so the children of those who have money can study.
世界如此之大，同时又如此之小。
The only performance standard is 'Zero Defects'.