Wallace places emphasis on the word "adjust" because he is addressing our realities and way of thinking as "default." He expresses the importance of paying attention to your surroundings, and adjusting to other perspectives and ways of thinking. He compares our ignored experiences to the water fish swim in but were never taught to notice.
D:a peace of land projecting into water
the downfall of the protagonist
Stern is a serious and unrelenting manner usually in a authoritative way while yearns is an intense feeling of longing for someone lost or that you separated from.