The use of "you" here is a substitute for the more formal and less often used third person "one". Using "you" helps the writer bring the reader emotionally into the story and make him identify himself with it. "Time seems (to)pass. The world happens, unrolling into moments," > he is describing the thoughts of someone who observes life passing and the world going on (maybe he is not feeling a part of that movement and activity. Maybe he feels left behind or not included in it."Time SEEMS to pass suggests this.)

"and you stop to glance at a spider press to its web". > the subject is contemplating the very tiny world of the spider next him in contrast to the great big world farther away. You have to ask yourself if and how a person speaking the target language would do the same thing.

There is a quickness of light and a sense of things outlined precisely and streaks of running luster on the bay. > This is a very American style of English. The writer is setting a mood like an impressionist painter does with dots and splashes of color instead of firm, narrative lines. He is describing the effects of the daylight, how it outlines everything and makes bright reflections in the water in the bay. The subject is staring at things around him and contemplating them. Without more text I can't tell you why, but it is a description of a "frozen" moment of contemplation.