An ISTJ i know has "I don't want to be mean" personality factor, which can manifest itself through him being nice to people even when they are annoying him, so how would i know if i am annoying him?
Maybe i should wait for him to start conversations instead of initiating them myself?
Wait for him to approach me instead of the other way around?
I wish there was some way i make him brutally blunt over night :P
(has no idea if these are typical ISTJ characteristics)