lol not all ISTJ's are that serious. In fact, I don't even like hearing about the seriousness right there. They must be very strong in some of the MBTI categories.Thus this came up in their use of Fe, which was Trickster. They were not really concerned with shared values (generally calling society an "insane asylum"), but when I was having problems with people, they appealed to external values, and even overestimated them, as Berens even says. Like suggesting I had trouble getting girls because I would sometimes have wrinkes in my clothes, or because they saw me with my shirt coming untucked sometimes. Yet one girl I liked would hang around with a bummy guy who was dirty from head to toe. I tried to tell them that couldn't be it, but then they appealed to their age and knowledge. So again, it was confusing for them to call society an insane asylum, but then criticize me for not going along with it. But that was their way of trying to motivate me to grow and survive in the world. When they did articulate Ti "principles", they were quite literally, "critical parents".
All of this came to mind recently, when at work, I was complaining about something. A lot of people in supervisory titles in this job seem to be ISTJ's. Everyone knows the system is screwy, but ISTJ's don't seem to like to hear complaining (unless they're the ones doing it the many times they're frustrated about something). So I get lectures about "being happy you have a job" and "it takes time to 'earn' your way up to seniority where things are easier", and then suggestions about looking for a new position. I didn't ask for any of that; I just voiced frustration with something. But that's what they do, and it was the same way with my parents. It seems that if the dominating type of society is ESTJ, then ISTJ (whom Keirsey called "the Inspector") is the supporter and enforcer of the system, even if they don't like everything about it. "That's life; just deal with it" is their motto.
My brother seems a little different, but then that's probably because he's younger. He's more like our parents in their younger, rebellious age, and his Ne and Fi haven't developed yet. He's like them in being totally unimpressed with type theory. He thinks it's just another category or "box" people are put into like race, (apparently, a negative reaction to Ti, and a sign he's not an ENTP, as he seems like in some ways) and everybody is just who they are. My parents also can't seem to get too interested in temperament theory (probably too abstract for them, still), but they're not as openly skeptical of it as my brother. They've basically "mellowed" in their age, and are also remorseful for being so cold in the past.