That Sardonic Smile

Sometimes it's fun to learn the origin of words. Check out how Pausanias (Description of Greece 10.17.12-13) says we got "sardonic":

Neither poisonous nor harmless snakes can live in Sardinia, nor yet wolves… Except for one plant the island is free from poisons. This deadly herb is like celery, and they say that those who eat it die laughing. Wherefore Homer, and men after him, call unwholesome laughter sardonic.