I believe that the speaker in "Invictus" considers independence and control most important in life. He says that "he is the master of his soul", meaning that no one else can control it.
I believe it would be a soliloquy. A soliloquy is defined as a person speaking to themselves without any regard for someone that may hear it (or oblivious to them).
I usually tell them thanks for your input even if it really wasn't needed or wanted then I take a deep breath and continue about my day. I could improve by trying to see from their point of view.
