The Moon-Saturn square creates inner pressure between the need for warmth and the demand to hold oneself together, endure, match expectations, and become adult too early. The Moon wants softness, protection, emotional response. Saturn answers with coldness, rules, distance, usefulness, and fear of weakness. With the square, the person may feel that feelings interfere with survival and vulnerability is dangerous. Therefore they close, become cautious, hard on themselves, and sometimes seem darker than they really are.
Interpretation