I can't imagine anyone with parents that never had "do's and don't's." Do's and Don't's are "drivers." The issue here is perfection. The "be perfect driver" first presented to the complaintant (Emily) by her parents is preventing the friendship (Emily's) from moving forward as a threesome with everyone taking the primary I'm o.k. you're o.k. position. Sarah is "o.k." to Emily's friend, but "not o.k." to Emily.