Countertransference is related to the original term “transference,” through which (according to Austrian psychoanalyst Sigmund Freud) patients transferred their feelings from key individuals in their early lives onto their therapist. Countertransference is a similar concept, but involves the therapist transferring emotional reactions (positive or negative) onto the patient.
Although countertransference will not necessarily damage the therapy process, it is something that all therapists need to be aware of when dealing with patients. They especially need to clearly understand how any countertransference is impacting the therapy relationship and process, whether positively or negatively, so they can act accordingly.
For more information, see About Counseling/Psychotherapy in the Mental Health section.