A social worker needs to build rapport with clients, (via self-disclosure - know, like and trust factor) so the client is willing to open up to them and to provide any and all information about her problem/situation Using theory in practice can help social workers create a treatment plan, increase a sense of security, and explain and predict occurrences in the client's life. A social worker needs to build rapport with clients, (via self-disclosure - know, like and trust factor) so the client is willing to open up to them and to provide any and all information about her problem/situation Using theory in practice can help social workers create a treatment plan, increase a sense of security, and explain and predict occurrences in the client's life.