We have already quoted Rashi Koheles here:
“גם את חכמת העולם אשר נתן בלב הבריות לא נתן הכל בלב כל אחד ואחד אלא זה קצת וזה קצת…”
An aphorism to illustrate:
“A fool knows more at home than a wise man at his neighbour’s”
Spanish proverb quoted in “The Life of Reason” by George Santayana
(And another one already brought here.)