Most type 8s I've known often appear calm and thoughtful for what it's worth. From a few seconds of thinking about it I think they're all T types.
Anyway, I don't think 8 is about anger at its core. The impression those kinds of people give me is that they have an automatic feeling of entitlement to everything. The anger is more a reaction to having that sense of "possession" challenged, maybe. No, I'm less sure of that. 8 is maybe more like a more energetic 5, trying to assimilate the outside world into the self than simply "possessing" it. At least that's how it seems to me.