1. "You are just a shill for (insert company, political party, etc here), how much are they paying you?" Read about that one here.
2. "What-ever." Which is code for "I got nuthin'"
3. "We'll just have to agree to disagree."
I just hate that last one, and it is the typical refuge of someone intelligent that has walled off their desire, but not ability, to learn about a given topic.
For me, I can't "Agree to Disagree" about a scientific topic. If I'm wrong, please show me the evidence-- convince me. If you're wrong, it is important that I show you my evidence and convince you.
Open hearts and minds can agree to find Truth,
and discussion of evidence is the first step. Scientists and
teachers are, by nature, compelled to do this
Hair combing poster child Albert Einstein once said, "I'm not interested in being right, I am only concerned with whether I am or not.".
This sentiment encapsulates the approach of most scientists. Being right is not our job. Testing a hypothesis and finding support for it, or evidence against it, is our job. Our goal is to be right or wrong, just not somewhere in between.
As teachers we synthesize the information we have, distill patterns and form interpretations and conclusions. This is what we teach, it is "right" until someone shows us otherwise. As a teacher, I care too much to let you be wrong, so on subjects where I am an authority I feel a sense of duty to add my thoughts. In subjects where I am not an authority I feel a need to learn.
When discussing a topic with a scientist bring real evidence, not bluster, accusations or finger pointing. Leave anecdotes, hearsay and flimsy evidence at home. Disagree on leaving the topic open ended. Agree to civil discussion and learning. Agree on seeking the truth, as the truth has no agenda.
We never have to agree to disagree if we both agree on the Truth.