Fear is a common origination. Can come from other things as well. Unexpressed grief. Trauma. Etc.
I believe anger is the root of a lot of chronic disease. It’s also very addictive and an easy emotion to manipulate. Politics do this very well.
Makes the divide and conquer much easier. War creates trauma that divides further from the truth that we are one.
Quite the tool. For me, better to feel it, get to root, and transmute.