La Primavera, "The Allegory of Spring" is the english title, is Boticelli's second most famous work, (after "The Birth of Venus")
Basically, so many people like because it's beautiful. It's an image of Springtime with beautiful women. What's not to like?
The painting's theme is obviosly a classical image of Springtime. Many classical deities and figures are in it: Aphrodite, Cupid, the Three Graces, Flora, etc. Aside from its importance as piece of Renaissance art, the painting's a record of some of the influential Florentine personalities from the 16th century. The Grace closest to Aphrodite has the face of Caterina Sforza, a daughter of Galeazzo Maria Sforza, the Duke of Milan. The face of Flora is Simonetta Cattaneo de Vespucci, the same woman as in his "Birth of Venus" (she was a relative of Amerigo Vespucci!).
