David narrates his own life with a warmth that does not exclude self-criticism. His central flaw — the 'undisciplined heart' that loves unwisely — drives every major plot decision: his worship of Steerforth, his marriage to Dora, his blindness to Agnes. He is not stupid; he is emotionally governed. His growth from a boy who loves surfaces to a man who values substance is the novel's central arc, and Dickens renders it with an autobiographical intensity that makes David feel less like a character than a confession.