At day 3, many people are tired and sore. They have bottomed out. This is a hugely significant day because it represents the turning point, the time when people get in or get out of the Wilderness mind set. Most get into it, in part because they really have no choice. At this point, the sub-culture forms.
Every group has a culture of some sort.
If we're successful, that culture is an incredibly powerful bonding experience. This spiritual connection can certainly happen outside of Wilderness, but somehow Wilderness serves as a catalyst for it. To truly recognize it, we must get out of our routine. We came from Wilderness. Like so many genetic issues, it often takes an environmental trigger to awaken that gene.