As a nurse of 13 years I understand your frustration when you see a dying and suffering patient who's life is merly prolonged at our hands (ie healthcare workers). But I have to ask what the specific cirumstances were. Did the patient have a living will or power of attorney? Was the family making decisions for the patient?
Personally I think euthanasia IS wrong, but I don't see anything wrong in witholding treatment if the patient requested it. On the other hand, I think it's just as bad to continue aggressive treatment in a patient who is dying and no longer wants to treatment.