Satan was nothing less than the Arch Flatterer, according to Milton. Dante put flatterers in the eighth ring of hell, right beside tyrants and murderers. In societies that were hierarchical, like those in the Middle Ages and the Renaissance, flattery was considered perilous because it was a means of upsetting the divinely ordained social order. If you brown-nosed the King into making you a lord, you were unfairly fiddling with the status quo. But flattery began even before Eden.
Chimpanzees groom each other all day long as a strategic means of advancement.
You can even make the case that it's evolutionarily adaptive behavior. The ancient Egyptians flattered themselves that they could outwit death. They almost always get it right. But the blossoming of the individual during the Renaissance changed the nature of flattery. When people began to think of themselves not as serfs or cogs but as unique individuals, flattery became more personal.