ISTJs are weird. They have their own oddities beneath everything that might come across as being normal to an INFJ. ISTJs have amazing self-discipline and expect the same from others, to a particularly high standard. It drives us INFJ people insane when it seems that all you care about is routine. However, order is often the very thing that we need in our lives (which is highly guided by feelings despite our own analytical nature). INFJs view ISTJs as being relatively unemotional, and possibly even robotic, but it’s far from unimpressive. The capability to take most things as constructive criticism is very respectable.
You know a person's probably an ISTJ if you see something like this when they accomplish their goals...
But despite the ISTJ's straightforward nature, INFJs see them as being more dependable and responsible individuals than themselves. They register INFJs to be very honest for the most part, so we don’t have to feel worried about being manipulated (actually, INFJs probably do more of the manipulating between the two). We might sometimes find the ISTJs' lack of open display curiosity for the mundane to be frustrating and a sign of incompatibility between our intelligences. INFJs wish ISTJs were more sentimental and “deep” with their conversations in a relationship, and will try to open them up. However, it’s not that INFJs are unsuccessful with this, rather it is the fact that ISTJs prefer to talk more about day to day things rather than the imaginative or the theoretical. This can be frustrating for the INFJ, but we need to understand that that’s who they are, and that there’s not much “figuring out” to do when learning about them.
Regardless, ISTJs are a very functional and structured type, and INFJs admire their consistency. It might be hard to communicate between the two to satisfy the INFJs needs, but it’s not impossible; it just requires more patience and understanding on our part. We appreciate your ability to support us when others won’t, and though you might not be able to understand certain parts of the INFJ's abilities, know that we are always ready to care.