The Wrath of Hera
Although Zeus's infidelity angered Hera, she tended to take out her feelings on his women instead of him. Granted, most of the women pursued by Zeus tried to escape his advances. But that didn't matter. Hera blamed the women and punished them.
That Pesky Fly
One of the best-known stories of Hera's wrath tells of her vengeance upon Io. As you recall, Zeus seduced Io and then transformed her into a white heifer. This stratagem didn't fool Hera. Pretending to believe Zeus's claims that the heifer was an ordinary cow, she asked him to give her the heifer as a gift. Zeus, who didn't dare refuse his wife, consented and gave Io to Hera. Hera placed the heifer under the guard of Argus, a monster with a hundred eyes.
Zeus felt sorry for Io and sent Hermes to release her. Hermes succeeded in slaying Argus and setting Io free. But that wasn't the end of Io's persecution. Hera found out Io had been released and sent a gadfly to torment the heifer. The gadfly followed Io around, continuously stinging her. Io ran farther and farther away in her attempts to avoid this torment. Eventually, after she'd begged Hera for forgiveness, Io was returned to her true form.
Persecution of Mother and Son
Another famous story of Hera's wrath is the myth of Alcmene and Heracles. As you know, Hera persuaded her daughter Eileithyia to prevent Alcmene from giving birth to Zeus's child. Heracles was born anyway, making Hera even angrier. She transferred her anger to Heracles.
Hera did everything in her power to punish Heracles, attacking him in many different ways throughout his life. She sent serpents to kill him in his crib, made him a slave, and drove him to madness (which caused him to kill his own wife and children). Throughout all of these torments, Heracles behaved like a hero, so Hera never truly got the better of him. (The life of Heracles contained many exciting adventures; Chapter 19 gives you more about this great hero.)
Even though Hera spent much time trying to make Heracles' life a living hell, her hatred didn't last forever. When Heracles died, he ascended to Mount Olympus, where he reconciled with Hera. To show good faith, Hera gave him her daughter Hebe for his bride.