Do you know what the technical definition of "positive feedback" is? It is not the same as "good" feedback. In an amplifier, positive feedback is feedback that increases an input signal, in phase with the input -- that is, in the same direction. If a signal has a positive voltage then positive feedback will tend to increase the voltage. If it is negative, positive feedback will increase it in the negative direction.

One example of positive feedback is the squeal that you sometimes hear when someone is speaking into a microphone, where loudspeakers are in the same room. The speaker's voice gets amplified by some electronics, which send it to the speakers, which then are heard by the microphone, which then amplifies the sound even more -- until the system goes out of control. The sound you hear then coming out of the speakers is not an accurate replica of the original sound, but it depends almost wholly on the characteristics of the sound amplification system.

Some "music" groups make deliberate use of this virtually-out-of-control system to produce sounds that they seem to like.

In the case of people, I generalize from what I think happened to me as a child. When I was afraid, and showed that fear, it induced my mother, who could not stand to know about more fear, to attack us (me and my brothers) in an often physically violent attempt, accompanied by verbal expressions of hatred and condemnation, to stop us from expressing the fear. Of course, the result inside of us was a spiralling increase in fear. Instead of greeting anxiety with comforting, she greeted it with more anxiety-producing actions. So a positive feedback loop was established, which ensured an ever increasing amount of anxiety until our systems could no longer take it -- and went "out of control" in one way or another. One way to attempt to control the unbearable anxiety is to blank out. Of course, my mother's frequent reaction to that was to lash out even more. So the tactic of blanking out to try to control the unbearable was not fully successful -- which meant it was all the more likely to be utilized, since as a child I could figure no other way to deal with it.

So "positive feedback loops" (emotional disregulation) get established and reinforced...