When you tell people they suck at something, they are more likely to do worse.
When you tell them they are good, they are more likely to do good.
There is limit to how much this effects performance, but it is obviously there. People always try to create some sense of self and identify with "who they are", thus work towards retaining and fully claiming their own identity. (I am a peaceful person. *works harder to never get violent, even if he/she has the same proclivity for violence as anyone else*)
This self identification, when done artificially in a closed room in front of a computer screen by reading a profile of our type, causes us to accept something that will in the future reduce our maximum potential.
Normally, this identification would have been done by experiencing life's trials and slowly, bit by bit figuring out where exactly you stand.
I've seen this exhibited among A LOT of people through common things like horoscopes, or when personally exposing them to MBTI and socionics over the years.
Unless you have some sense of self, can detach from this effect and you're not a person to seek safety and identity in the arms of personality typing, I strongly suggest YOU STAY AWAY FROM IT. I have come to believe it can only do you harm if you choose to go deep into it and identify with it.
On the other hand I find it a useful tool to observe and understand people's tendencies and patterns in personality and behavior, but one should never try to align with a pattern someone is suggesting for them personally. In my opinion, socionics should be a tool for detached, noncommittal/casual observation.
NEVER a firm lense of reality, or a tool for introspection.
This suggestion of mine is often rejected thanks to a feeling of safety and fulfillment people may get from identifying with a group, or from definitively claiming a particular set of personality traits as their own.
It's to say that there are uniform ways of best and most virtuous ways of approaching all facets of life and some people will simply be able to do more than other people when looking ALL the available areas. To say "everyone is different" as a justification for some people sucking at one, or many things is not to explain. It's simply to justify and make them feel good.
You're not "different", you suck. Work on it.
If you're "just different", you're gonna use it as an excuse to sit on your ass and "stay different".
Had you not had said excuse, your life would probably have been a lot better.