Depends on context.
I usually get angry at underlying assumptions (like: if he says that then he must be assuming at some level that a and b and that pisses me off).
So that tends to mean I have less capacity at getting angry at strangers (not knowing them as well) with which I'll be 'colder' in case of conflict.
Some ppl are quite emotionally unrelatable to me and then it's just confusing. For example people with strong psychopathic traits.
I get angry when people lack respect towards me/ don't respect my space, when people bullshit me, negative people as I feel it's infectious and I don't want that crap on me.
about the respect thing It's quite hard to define in words for me (NT.

), I don't really care about most things.
I guess it gravitates around competency (treat me as if i was incompetent without very solid justification and we're going to have a problem).
For example, I won't get upset enough to 'yell' in most traditional conflict situations but I can tell someone to fuck off pretty loudly if they give forced/unwanted advice in an area where I am competent and they are not. The trigger is not the fact people want to 'discuss' the topic which I am more than fine with, it's related to disregarding my input (weak trigger) or Si-judging me to death, stating things as absolute without solid backing (strong trigger). It usually takes multiple instances of such situations to get me 'angry'. I have to reach a point where I don't see the conversation as fruitful and simply a waste of time in addition to being patronizing to me (ie: if u think ur right give me solid reasons, if u just judge me because of some external frame that has nothing to do with ur knowledge of my decision making which I have previously demonstrated to be coherent and explained then please go away - if reason and polite requests fail, i will yell)
Example of a situation:
I make it very clear I don't need input on the purchase of a new computer. The computer is already purchased and I'm easily in the top 10% of the population in computer-related-matters-fluency. I also had the best information on my factors in selecting said purchase, which I did not disclose with that individual.
The person communicates in a way that implies doubting my decision (offering alternatives without having the technical know-how, and ignoring the fact that the purchase is already done, makes statements questioning the financial-sense of the purchase etc.) - such unwanted/baseless inputs have been provided many times before and my input doesn't seem to have 'convinced that person' that I can indeed make my own decisions without getting unwanted advice.
After a first and second warning where I make it clear I do not wish to have this conversation I will start raising my voice
Until, usually around the 3rd / 5th time I say 'no thx' I will start yelling loud enough for them to go away.
I'm not very proud of it but I don't find other ways to help getting rid of this type of nuisance.
I often get into conflict with my father (alpha male extj) who has alot of knowledge and is a very smart man, however the lack of flexibility and habit of passing judgment before hearing me out on any and all topics + repeated such interactions tend to drive me nuts. I however enjoy interacting with him in other instances (as stated previously, very knowledgable)
Which makes me think - I think I 'm more likely to get angry at people whose competency I recognize in some field or another. I seem to be triggered by people's actions that seem to indicate that , whatever their reason is, they question my own 'competency'. For example if someone tells me I'm good at something yet keep trying to micro manage me. To me the action of trying to micro manage me and ignoring my input makes the first statement hypocritical/insulting/condescending (all strong 'yelling' triggers)
My main drive in 'cold' anger (staring at you like I'm going to slap you and explaining politely how and why you should learn some manners) is to correct disrespectful behavior towards me, my main drive behind 'snapping at people' (hot anger) seems to be me wanting to 'get them off my back' at which point I am usually fed up enough not to care if it doesn't really solve the issue as I'm just trying to dissuade them from interacting with me in the same fashion again)
I'm a 7w8 so I guess it makes sense (yelling/most upset at attacks on my core values - my ability to think logically/my ability to remain positive minded. and secondary drive for status / respect - for example I have a history of putting rude waiters 'in their place' (just an idiomatic expression, i don't mean anything superiorish by that) and have them eat out of my hand the next time i go to that cafe/restaurant )