The South Node sits directly opposite the North Node and describes the familiar, almost automatic patterns a person tends to fall back on — traits that come easily but that the rest of the chart suggests aren't where the real growth happens. It's often described as what's comfortable rather than what's wrong, since South Node qualities are frequently genuine strengths — the caution is against over-relying on them at the expense of the North Node's less comfortable direction.
Because the North and South Nodes are always exactly 180° apart, a chart never shows one without implying the other — they're read together as a single axis of growth.