This issue we'll start with ISTJs and ENFPs and examine where they might fit best and some of the possible weak spots for each.
Our friends the ISTJs are often considered to be the backbone of many organizations. They are frequently reliable, hardworking, detail-oriented, and conscious of timetables and schedules. You can usually count on them to do their assigned tasks the right way and respect the hierarchy of the group. Consequently, they often prefer organizations that are stable, structured, task-oriented, orderly, staffed with realistic, hardworking folks like themselves. The military fits many of those criteria.
Some areas where ISTJs could run into problems include appearing or becoming rigid in their thinking (Don't confuse me with facts. My mind's made up.). They can expect others to adhere to the same standards and have the same attention to detail they do. Others might incorrectly believe they don't care about people because many ISTJs dislike small talk and chit-chat. ISTJs can focus a lot on daily activities and spend less time on future planning. Some develop a pessimistic outlook and may dismiss new ideas as impractical (We tried that before and it didn't work.).
Switching to the opposite type, ENFPs have many fine qualities that make workplaces better. Many people of this type are good at recognizing the need for change, and get started at it making it happen. Their people-centered nature helps them see possibilities that might improve conditions for others. ENFPs are often good at showing their appreciation for others. A good work place for them includes time for socializing and individuality, has lots of variety and challenges, is flexible, emphasizes fun and idea generation, and is low on bureaucracy and rules. They often prefer casual environments, particularly if there's a strong focus on helping people.
Some areas where ENFPs might struggle include starting lots of projects but never finishing any, or jumping from one idea to another without developing their concepts more fully. In their enthusiasm and excitement, they can overlook details and facts that conflict with their great new ideas. A side effect is spending so much time pursuing new interests that they attempt too much and overload themselves, which can lead to burnout. Too many interesting ideas can also create decision-making trouble, which might result in procrastination.