Hermes was the Greek god of trade, sports, travelers, thieves and the patron of poetry, and as a result there are many interesting facts about him, including that he was a notorious trickster and one of a select few gods who could freely travel to and from the underworld. Hermes also frequently meddled in the affairs of mortals, although his influence was often benign.
Hermes was the son of Zeus and Maia, and his primary task was to serve as the herald to the gods. Like many gods, Hermes enjoyed interacting with mortals, whether for amusement or to offer his help. He appeared to help Perseus defeat Medusa for example, and helped to free one of Zeus's lovers (Io) from Argus the giant.
His reputation as a trickster likely originated from his youth, when he stole cattle from Apollo on the day of his birth, thus cementing his reputation and becoming the patron of thieves.
Despite his reputation and patronage, he was also thought to be associated with both fertility and good fortune, with festivals (known as Hermoea) often being held in his name.
One of Hermes' sons, Abderus, was a close friend of Hercules before meeting his death at the hands of the Mares of Diomedes.