In the second episode of HBO's Westworld, "Chestnut," a guest named William arrives at the park for the very first time. He trades in his normal clothes for custom-made Western gear and prepares to embark on his expensive adventure in the theme park, but first he has a choice to make. William is faced with two walls lined with hats, one side all in white and the other all in black. Deciding which hat to wear determines the course of his journey, and the kind of person William wants to be while in Westworld. The white hats and black hats in Westworld are a lot more than a fashion statement.
Though it's a little heavy handed, the metaphor behind the choice is clear. If William chooses a white hat, then he's a hero. If he choose a black one, then he's a villain. According to the Westworld website, the hat a guest chooses "embodies how you intend to play it inside." This is typified in William and his friend, Logan. Logan wears a black hat and indulges in every vice Westworld has to offer, bedding down with numerous hosts, being rude to everyone who crosses his path, and engaging in violence with abandon. William, on the other hand, makes a different choice.
While in the park, William shies away from the sex and violence. He doesn't even seem interested in Westworld until he comes across Dolores, the Disney princess of a rancher's daughter. Dolores exists in the park to feed people's hero fantasies – or their most villainous ones. When Dolores' family home is attacked by bandits, guests have the option of rescuing her and taking advantage of her gratitude (playing the hero) or killing her noble beau and taking advantage of her pain (playing the villain). Though he does not take part in that particular narrative, William's desire to be a hero plays perfectly into his interest in Dolores; in most narratives, she's the archetype who would act as the love interest or "reward" for an action hero. (Gross.)
The black and white morality is perfectly at home in the park's Western setting, which plays heavily on the tropes of the genre to create a romantic adventure for the guests. Obviously neither a white hat nor a black one means anything about who a person is; just because William wears white and refuses to engage (at first), does that make him a good person? Just because the story he's drawn to paints him in a more positive light, does that make him better than anyone else who is using the park to live out a fantasy?
Of course, these are the questions intentionally posed by the show. The choice says more about how the guest perceives themselves and how they want others to perceive them than it does about who they really are.