At one point the authors discourage closing your eyes while singing in worship. They note:
"Many musical worship leaders encourage members (by either word or deed) to close their eyes in pursuit of private emotional intimacy with God in the context of the corporate gathering. Now, no one in their [sic] right mind would argue that closing one’s eyes in corporate worship is categorically wrong. And many close their eyes in the corporate gathering simply to take in the sound of the singing more fully. But we would be wrong to encourage people to think of corporate worship in terms of shutting out the rest of the congregation to have a privatized emotional experience with God" (117-18).
I was struck by that because I sometimes close my eyes while singing in corporate worship and had never considered whether or not this contributed to making worship a more "private" experience. The authors anticipated my first thought in objection—namely that we typically pray with our eyes closed—in a footnote: "We close our eyes for corporate prayers too, but this is an act of reverence as we bow our heads, not an effort to forget about the people around us" (p. 209, n. 6). We might respond that closing one’s eyes while singing might also be an act of reverence (and a part of prayer as well).
I am glad the authors made me think about this. It is a good corrective to some of the hyper-individualism of contemporary worship, but I was not completely convinced by their argument.