You start to realize connections between experiences and things that push your buttons, and things that have touched you in those vulnerable areas and what-have-you. And they form a little collection over time - at least I do - and as time progresses and new things are learned, you kind of sift through those things until they're air or danceable, you know? But they start as this thing that's either too hard or too soft to dance to.
In the course of a healthy debate, we prioritize different goals, and the different means of reaching them. But without some common baseline of facts, without a willingness to admit new information and concede that your opponent might be making a fair point, and that science and reason matter - then we're going to keep talking past each other, and we'll make common ground and compromise impossible.