Unrequited love drives people to sui (immortalized in famous Goethe's novel). When it happens in therapy, it's even more destructive and humiliating. Could be like a parental and romantic rejection at the same time.

Also if a client is feeling rejected, but is also dependent on the therapist and so keeps going back, it could be like experiencing the rejection over and over. I found it was like having a weekly IV drip of poison.

Where else would rejection or unrequited love be used as an alleged tool for healing?