The jealousy of Hera, queen of the gods, is the biggest source of conflict for Heracles' entire life. As one of Zeus' many illegitimate children, Heracles is a constant reminder her Hera of her husband's cheating ways. Her jealousy is so intense that she makes Heracles go crazy and kill his own children. (Wow, that's over the line.) Of course, if it wasn't for this horrible event, Heracles would never have performed his Twelve Labors, and her never would've been the immortal hero is today. So, in a way, it's Hera's jealousy that makes the man.