It’s not about good things or bad things

Negative feedback loop: X is added to the system, which causes less X to be produced. Over time, the rate at which new X appears goes down.

• This is the more common one in biology. As something starts to build up in your body, your body makes it so you don’t produce it as quickly (so you don’t ‘overdose’ on the chemicals you are making)

Positive feedback loop: X is added to the system, which causes more X to be produced. Over time, the rate at which new X appears goes up.

• This is more rare because it pushes to an extreme. Example might be birth, where pressure on the uterus causes the release of oxytocin, which causes contractions, which causes more pressure, even more oxytocin, etc. till birth is completed