I listened to The Pet Sounds Sessions box set recently and noticed a handful of features. "Wouldn't It Be Nice" contains an instance of polysyndeton, a rhetorical effect in which conjunctions are repeated: "Maybe if we think and wish and hope and pray it might come true." Having "and" so many times isn't strictly necessary, but its repetition gives a sense of the earnestness of those actions.
Additionally, the musical rhythm of this line is such that "think," "wish," "hope," and "pray" all occur on downbeats, and this also provides emphasis.
