Black Rock City gave me the same relaxed feeling as did Beautiful Dreamer by S. Woodson.
The PC doesn't have any clear goals, they just have some time to spend at Burning Man festival before a dust storm hits. There are no right or wrong choices, no pressure; you explore different branches of the game, learn things about the bizarre city and its inhabitants, feel free to try even ill-advised actions like (Spoiler - click to show)jumping from a flying carpet.
The game has 2^6=64 endings and a considerable variety of possible actions across the branches; in addition to standard adventure verbs like "examine", "talk to" and "kiss", sometimes you can choose "believe", "sass", "admire", etc.