Experience shows that this transference very soon becomes the source of resistance. Love is only a seeking for love in return, Do, ut des [I give, that thou shalt give]. If the patient notices that love is not given in return or that it has not reached that degree which he expected, defiance enters in place of the love, which in turn manifests itself as active resistance.

On situations of transference in doctor-patient relations, in Sadism and Masochism : The Psychology of Hatred and Cruelty, Vol. 1 (1939), p. 46