I am engaged to an ISTJ and my best friend is ISTP. Dangerous territory, since I'm an INFP; luckily, though, I have some out of type traits with my F (tough rather than tender, questioning rather than accepting), so I can manage a masquerade as a T.
Anyways, in my experience, folks with S and T either account for people's feelings too much or hardly at all. For example, my ISTP friend used to constantly concern himself with the feelings of others, even in situations in which he should have only looked after number one! In the end, I would enter the situation, kick some ass, help him out, and he'd learn by example. Still kind of wimpy about stuff, but I've toughened him up some.
My ISTJ fiancee' seems to sacrifice herself for other people because of things like "Well, we used to be friends," and so on. Seems to me that her sense of duty is how she navigates, and sometimes it causes her to damn what it costs her personally. Very strange to me; I admire the whole duty-oriented style and I appreciate her values, but it's hard for me to imagine the past as being a powerful impetus for the future. Sometimes it is, but I generally don't look backward as much as she does. She also has this affinity for doing mundane things like buying cookware and making dinner that she's romanticized; the other day, she was sighing almost dreamily about carrying out errands and such with me!
In general, I find that T types care too much or too little about the feelings of themselves and those around them. ISTJs in particular seem to either care too much because of a sense of traditionalist duty or care too little from a sense of organizational responsibility.