Ah, I have a case study for this thread.
![Big grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I think I've mentioned that I spent high school sandwiched between an ISFJ and an ISTJ, more than once.
Habba's post rings true actually. The only thing I have to add is that the ISTJ had a stronger work ethic. Whenever we exchanged the occasional "How do you does" the main topic on her agenda was finding a job, or complaining about the current one she had. The main topic the ISFJ loved to discuss was gossip, "You'd never guess what happened to so-and-so!", things like that. Also, the ISTJ was less concerned with maintaining social relationships. She was loyal, but in a more hidden, underlying way. The ISFJ seemed to make an active effort in maintaining ties, even a year after I moved away.
If an item of reading was to personify an ISTJ in general, it would be a broadsheet newspaper: informative, detailed and more concerned with current issues.
An ISFJ would most likely be an entertainment magazine: concerned with interpersonal affairs, style & fashion, and celebrity gossip.
I'd say humour was another thing that separated them. The ISFJ was cynical and out-right sarcastic, or quoting inside jokes between herself and another. The ISTJ was more dry and subtle, and focusing more on observations. It was a bit more ruthless and cutting than the ISFJ's. Both of them loved quoting lines from their favourite SitComs and films. Referring to Habba's post, the ISTJ's humour stemmed more from the stupidity of everyone around her, whilst the ISFJ's humour stemmed from social oddities.
As would be expected, the ISTJ was more logical. During a group dispute, she would stand up for the one who was genuinely in the right, whilst the ISFJ would support the one who was upset. Both were generally passive in these matters, unless they were dragged into it.
I'm trying to remember other things about them.
![Thinking :thinking: :thinking:](/data/vbsmilies/thinking.gif)
Specific questions in distinguishing the two would be more helpful.