I cannot speak for you, but for me, and this took a while to figure out, it is a mixture of self-esteem issues and how I didn't ever confront people for how they treated me badly; and so I was angry at others for good reasons but never presented it in a way that led to fixing it, or closure, or self-protection; and the anger built up, and I was mostly angry at myself but didn't know it. And I had kind of automatic way of pushing all of that deep inside where it hid there and fermented, so that's why I seemed angry at everything.

Anyway, hope this makes sense. We are complicated, us humans, and it takes quite the digging expedition to figure us out sometimes. But I did it myself with tons of introspection and patience. And i read a lot of books, and I journal too. Take care and Hugs!