I finally got to use this phrase this weekend and was so excited. I actually got to use it about ten times. One of my patients (I work on a medical floor but he was hugely psyche) was demanding that staff go to his car and get junk food out of it for him. He would not give up but as soon as he went into multiple manipulations, including how I was a terrible person for not doing it, I just repeated "I'm sorry, it won't be possible". It was wonderful and eventually just shut him down with no loss of professionalism from me. I need to learn more phrases and how to use them, it makes life so much less frustrating.