Harto presto, si bien. - Baltasar Gracián

Be extraordinary in your excellence, if you like, but be ordinary in your display of it.

Confiar de los amigos hoy como enemigos mañana.

Never exaggerate. It is a matter of great importance to forego superlatives, in part to avoid offending the truth, and in part to avoid cheapening your judgment. Exaggeration wastes distinction and testifies to the paucity of your understanding and taste. Praise excites anticipation and stimulates desire. Afterwards when value does not measure up to price, disappointment turns against the fraud and takes revenge by cheapening both the appraised and the appraise. For this reason let the prudent go slowly, and err in understatement rather than overstatement. The extraordinary of every kind is always rare, wherefore temper your estimate.