To the OP, I gave it some more thought and it seems that I am much more likely to experience an outburst when the rask at hand was unexpected...like an automotive breakdown...or some task where I have not been able to gather the proper tools and do a little research into what might be wrong. I seldom have problem when I encounter difficulties performing tasks that I intentionally prepared for.
Is this a preference fault? I hope a few other ISFJ folk will stop by and offer their experiences and insight. I'd like to see if (as your OP suggests) there might be some corelation here...where we might take steps to address the problem?
I understand that part of the preference profile fo an ISFJ is to avoid conflict (or as I see it pointless conflict) ...an outburst at objects or processes is one thing but at people? It would have to be a very specific and intense provocation for me at least.
Patriotism is the last refuge to which a scoundrel clings...Steal a little and they throw you in jail, steal a lot and they make you a king
I have to admit i do have yelling outbursts .. although trying to control them .. My problem is everything has to be done a particular way ie Perfect, so when the flat pack instructions are in a foreign language, i'll just get on with it until i flip out and throw the screwdriver across the room .. but as quick as my outburst is, im calm again and i start all over again .. Because i do everything almost perfect i expect the same in return .. lol .. but flat pack items are not usually perfect be it instructions or missing screws ..