First of all, if we talk about vengeance, it is because there has been an insult, a wound, something which hurts, an injustice. Sometimes, it is a tragic event which breaks our life, as an explosion shattering everything. Then we have to choose between two paths: forgive or to hold a grudge. Cersei Lannister chose to take revenge.
A pennant in the wind, a pale but brilliant sun piercing the clouds, warriors imbued with solemnity in a boat, then we discover a figurehead in the shape of a golden dragon while the majestic music rises, choruses and percussions, to reveal to us Daenerys Targaryen’s army sailing towards Westeros with her three dragons.