I do carry anger inside, likely as a backlog that would naturally result from a temperament given to forming expectations and ideals. I remember it being there from early childhood and enduring through a variety of situations, so while it may be managed, it is likely a permanent feature. Actually I have a theory that I was bullied as a kid due to only being 98% successful at repressing it - I didn't lash out at other kids, but there was a vibe/look/tension that smelled like something really intense and hostile lurking underneath and made others uncomfortable (especially because the reason/target was unknown), others as in other kids who were failing kid-like to manage their own issues too. I think so because as an adult, people who have gotten close enough have told me that they detect this from me, even if it has never been expressed toward them and is totally unconcerned with them. I have also been told that I seem to lack "cold" anger, just having "hot" anger if any at all, and that this is uncommon.
I have managed anger worlds better in my 20s than before, not so much like disciplined control but more it finally striking me, in more serious depth, how it was to other people - i.e. getting smacked by a few fair warnings about self-absorption. Which is not always what anger is about - I wish I could say mine is righteous or justice-oriented, but nope, it was inward, ashamed and perfectionistic.
However, I say "was" because now I'm catching on to another dimension of it, that the introjection has been a defense and not the true form of the anger. I doubt that I ever truly hated myself as much as anger pointed in that direction will make one think. Parsing out which anger really goes where is a monumental job I am still yet to even close to master, as just getting to the point of seeing that this was the case took forever. However, I do remember what it was like as a kid, before I was capable of introjection on an adult level, and that is an important clue. I typically felt flashes of anger in response to being pulled away from doing something I loved or was intensely focused on, often creative activities or reading. After that, rigid expectations being frustrated was another source - like that something would happen at a very precise time.
So, re: OP question...all I know is that understanding it helps, although I have not gotten any understanding from trying to understand, but only from experience. Maybe that's the only way to get it, but if it's not the only way, getting it another way would be much nicer indeed.