Not possible for a reasonably intelligent, reasonably sane, reasonably stable person to be 'bad' at using the dominant function.I haven't been able to find much info on this recently in researching MBTI and function theory, but I've been wondering to what extent one's ability/skill with the dominant functions varies between types or how someone that's terrible at their dominant function would look like, depending on the function.
Descriptions of both functions and types appear to emphasize individuals that are good at using their dominant and auxiliary functions, but it's hard to find information on types that are bad at their functions. To me, it looks like every description is biased towards individuals that are good at using their dominant function or at least average, while ignoring everyone else.
I think there would easily be many, many people of each type that are bad at their dominant fundtion, but still prefer it and are better at it relative to their other functions.
Often times, it seems this is chalked up to being unhealthy or something, but it seems like this is a very important, overlooked thing that can lead to many mistypes. If someone becomes interested in MBTI and looks into functions, they could easily miss their type if they're bad at using their dominant function and assume they're something else regardless of health.
I could easily see how this could lead to confusion between different functions, where a dominant Ti user things they're Fi because they're not as good at logic or accuracy as other Ti dominants or an Fi dominant mistyping as a Ti dominate if they're not great at knowing how they're feeling or an Fe dominant mistyping as Te because they're not as good at Fe and so on.
I don't mean only a person mistyping themselves when trying to figure it out, but also outsiders mistyping them as well, or the person coming across as another type to an outsider due to how bad they are at their dominant function.
So, I'm wondering, to what degree does dominant function ability vary? What does it look like when someone is terrible at using their dominant function? Does it always lead to an unhealthy state, and if it doesn't, how do they differ from others that have better use of the dominant function?
The problem would more likely be caused by someone using all other functions to serve the dominant one, which would lead to an extreme imbalance in over-all reasoning and therefore functioning effectively.
So, if, say for an INFJ, all functions are used to serve Ni, then the particular INFJ could look as though he or she were a different type, or an incompetent, e.g. an INFJ who has used, say, Fe energy/focus on Ni exclusively (or close enough) would seem uncaring, rigid, obsessed with some perfect adherence to a cause at the expense of caring for real individuals who make up the target for the INFJ's cause.
Again, using INFJ as an example, if the person is using up all his or her energy on gathering information, seeing all possibilities, unable to make a decision--too busy gathering, no harvesting--then others might view that INFJ as a 'lazy' INTP or 'a flaky' INFP, or one of those 'can't pay attention for more than a few seconds' ENFPs. And even, oh no! a sensor who can't succeed until his or her type is recognized.
Just extrapolate this to all other types, one by one, i.e. imagine any MBTI type using all other functions to serve the dominant one, and tease out what that might look like.
It will become apparent that any type would seem like either a mistype, stupid or otherwise incompetent, rather than someone who--for whatever reason--needs to spread the focus around, building up auxiliary, tertiary, and especially inferior function.
With the inferior function, however, one shouldn't focus 'too much' there either lest a massive energy drain occur so that yet again, a seeming mistype or 'don't care' type is perceived by others rather than the actual type in a lopsided state--to an extreme degree, while over-using rather than 'being bad' at using the dominant function.