Here is a collection of proverbs and quotes by smart people which I particularly like (some might be apocryphal):

• Без труда́ не вы́тащишь и ры́бку из пруда́ (Russian proverb)
• На вкус и цвет това́рищей нет (Russian proverb)
• De gustibus non est disputandum (Julius Cesar?)
• It doesn't make sense to hire smart people and then tell them what to do. We hire smart people so they can tell us what to do (Steve Jobs)
• Omnia mea mecum sunt (Seneca)
• Ama et fac quod vis (Saint Augustine of Hippo)
• It is a scale of proportions which makes the bad difficult and the good easy (Albert Einstein)
• Quid telo denique fiet? (Lucretius, De Rerum Natura)
• Erst kommt das Fressen, dann kommt die Moral (Bertolt Brecht)
• L'hypocrisie est un hommage que rend le vice à la vertu (François de la Rochefoucauld)
• The first principle is that you must not fool yourself... and you are the easiest person to fool (Richard Feynman)
• The more the universe seems comprehensible, the more it also seems pointless (Steven Weinberg)
• if inflation is not right then God has missed a good trick (Jim Peebles)
• I have done a terrible thing, I have postulated a particle that cannot be detected (Wolfgang Pauli)
• The measure of greatness in a scientific idea is the extent to which it stimulates thought and opens up new lines of research (Paul Dirac)
• The task is, not so much to see what no one has yet seen; but to think what nobody has yet thought, about that which everybody sees (Erwin Schrödinger)
• Every sentence I utter must be understood not as an affirmation, but as a question (Niels Bohr)