One of the most common uses of the FIRO-B is promoting team work. Since working with other people is the one common element of work teams, the FIRO-B is a great tool to explain why there is friction between two or more people. When you "click," or get along, with another person, it's seems as if work goes smoothly. When things go poorly, it's hard to get anything meaningful accomplished. The FIRO-B can explain why you get along well with some and not with others in your team. Likewise, you can use that information to make team work go more smoothly.
It should be no surprise to learn that two people are more likely to get along well together when the expressed needs of one match the wanted needs of the second person. For example, if one person has an Expressed Affection score of 5, and the second has Wanted Affection score of 5, we have a good match. If all three scales match, you would have a perfect match and likely little difficulty working with the other person. Of course, such a combination may not happen often. In fact, most people find that if they match on two of the three scales, they get along relatively well.
To be more precise, it's unnecessary for the scores for both people to be exact. Usually if they fall in the same range, that's enough. So if one person has a low score on Expressed Control and the other has a low score on Wanted Control, then they will likely get along well in that regard.
When there's a mismatch on the scales, disagreements can result. Logically, when there's a mismatch on the highest total need, disagreement can be most difficult. If your highest Wanted Need is Control, and the other person's lowest need is Expressed Need is Control, the mismatch will be stronger. Likewise, if the mismatch occurs on your lowest total need, the disagreements will probably be less daunting.