This quote by W. Somerset Maugham suggests that just a typical person has the ability to consistently perform at their greatest level. It suggests that those who are truly exceptional are not able to keep their peak performance all the time. It recommends that achievement is short lived which it is difficult to sustain quality over an extended period of time. It also implies that mediocrity is more trusted and consistent than achievement. This quote motivates us to strive for greatness, but to also be aware of our restrictions and to accept that we may not constantly be able to perform at our best. It is a tip that we need to not be too difficult on ourselves when we are unable to reach our greatest capacity.
"Don't lower your expectations to meet your performance. Raise your level of performance to meet your expectations. Expect the best of yourself, and then do what is necessary to make it a reality"
"The man who makes everything that leads to happiness depends upon himself, and not upon other men, has adopted the very best plan for living happily. This is the man of moderation, the man of manly character and of wisdom"