If I can't have it, it must be good. If the focus is on what you cannot do, without balanced understanding of belief and behavior, it can create an appetite for what is forbidden. A legalistic attitude in children. If I'm keeping the rules I am right regardless. If you are not adhering to the rules, you are wrong period.
Legalism offers little latitude.
It maintains a narrow scope of opinion, vision, and redemption. Legalism is a sad substitute for righteousness. An improper interpretation of relationships. An imbalance of rules focus can cause children to believe a relationship is a function not a fellowship. Love is understood in terms of a manual's definition or a counselor's explanation.