Children can be manipulative. Christian prayer is distinguished from magic precisely at this point. It is never manipulative, always trusting. We must trust God to decide what is good. Attempting to use a magical formula is manipulation in which a result follows mechanically if one does it the right way.
Prayer is never like that.
You cannot get the desired result just by pulling the right lever. Prayer is not mechanical, but interpersonal. We exercise our freedom in a relationship and expect the other person also to respond in freedom. In his farewell conversations Jesus encouraged his disciples to pray in his name , expecting their prayers to be answered. In a way this is much like the word about faith.