ISTJ

ISTJs are meticulous, factual, organized and they strongly value reliability, integrity and tradition. They use facts, figures and other concrete information to make “sound” decisions. 

ISTJs take deadlines very seriously and are tireless when working towards one. ISTJs don’t like having to depend on other people to get work done and prefer to do their work independently whenever they can. When they do have to work as part of a team, ISTJs may try to define roles and delegate work or create a well-defined process that they expect to be followed.  

ISTJs can be prone to developing a "my way, or the highway” attitude because they tend to be dismissive of ideas that aren’t based on fact or evidence. They also don’t have patience for people they decide are lazy or incompetent. 

Did we mention that ISTJs can also be judgemental? This is because they tend to measure everybody else against their own work ethic and high standards and other people often come up short. 

ISTJs like to follow rules and procedures and they focus on hard facts and hard work. This can make them inflexible and cause them to overlook the feelings of others.

Source: myBlueprint