Frye's intimidating words to McGee when confronted in his rented room had a profound effect in bringing home the danger he was in by pursuing John Doe. It forced Jack to rethink the confidence he had developed that the Hulk would not hurt him. I believe he retained his renewed fear & hardened attitude throughout the remainder of the series, but by the first reunion movie in which time the Hulk had not appeared in several years he may have softened somewhat.