You can't hear the name Aesop without thinking of his fables, and while it's unclear whether he was really a Greek moralist or simply a name attached to the tales Aesop's stories, and their lessons, live on.
These morals are often the first life lessons we learn when we're young, but we're also learning a bunch of different expressions we'll use for the rest of our lives from Aesop's fables.
Expressions like "slow and steady win the race", "revenge is a double-edged sword", "quality, not quantity", "look before you leap" and "one good turn deserves another" are so common we use them without thinking of their Aesop roots.
Another common expression with a very teachable story behind it- the lion's share:
7. To take the “lion’s share.”—From “The Lion, the Fox, and the Ass”
A lion, a fox, and an ass went hunting together and set to divide the spoils of their efforts between them. First, the ass divided the goods into three even piles, at which point the lion attacked and devoured him, then asked the fox to divide the food. The fox, taking a lesson from the ass, gave the lion nearly all of the game and set aside a meager portion for himself, which pleased the lion, who then allowed the fox to live. Another lesson gleaned from this tale? "Happy is the man who learns from the misfortunes of others."