Yes, I have. I've even made a thread about the possibility a while back. I just never test P and I'm not mechanical minded at all (which seems to be a trademark of the ISTPs). If it works, I'm happy and I don't really feel the need to how it works, if it doesn't and it's a technical piece of equipment, I'm pissed and lost in the sauce. lol...
In a lot of ways, I identify with the P function though; I think moreso within the last couple of years in my life. I've let loose more and become more comfortable in my environment and open to "the moment".
And I'm not anti-authority by any means, if it seems I've implied that. Hell, I'm an aspiring Police Officer; but I can be easily irritated with inane rules and more irritated with people that stand behind them, trying to uphold them, without even questioning why they're doing it. I guess my definition for that type of person would be a "tool".
I don't like MBTI anymore. lol
In strict Jungian terms, P is not actually a "function."
Being a P means that you extrovert the Perceptive function (in the case of an xSTx type, this would be Se.)
So, if you can't decide purely by whether the Judging or Perceiving profiles fit you better, try to determine whether you fit closer to the Si/Te mold or the Ti/Se one. To me, your speech seems littered with ISTP pragmatism--if "pragmatic" is one word that may describe you better than any, there's a good chance you're ISTP.
Let's consider the image you give off to others, for a moment. According to function theory, the difference would come down to this:
ISTP (Ti+Se) = Introverted Judgment+Extroverted Perception. People see mainly your flexible, unscheduled and adaptable side. While most of your time is spent in quiet reflection on Ti, placing all available data into an impersonal framework which becomes the standard for evaluating everything, your interactions with the external world are handled by Se, meaning you observe, respond and instinctively adapt quickly to changes in your immediate physical environment, preferring to do what feels right at the moment over planning out every meticulous detail.
You don't have to be mechanically-minded to be an ISTP; that's just a common interest for them. Others likely would not describe you as particularly controlling or organized, and you don't mind changing plans abruptly or not having a plan. ISTPs are good at improvising practical, real-world solutions to technical problems on the fly--they'd much rather learn by doing, through a hands-on direct experiential approach, than by reading books or learning through otherwise traditional means. Often, ISTPs entirely ignore the rules because they're too busy getting directly involved and doing. Due to the Perceptive function Se being extroverted, others see you as more curious than decisive (though internally/privately, via Ti, you are very decisive.)
ISTJ (Si+Te) = Most of your interactions with the outer world will be handled by Te, which organizes everything in your external world into logical relationships by which
useful goals can be completed. Te causes others to see you as more decisive than curious, although you spend the majority of your time in quiet reflection on Si. Si fosters fundamentally a "better safe than sorry" attitude--contrary to Se's ability to instinctively adapt and improvise in the moment, Si relies primarily on what its rich, distinctive memory for sensory details can recall with direct, literal precision.
So whatever has been directly experienced before is always the basis for how we should approach the future--consider what we *do* know for certain (Si) and have a detailed and strictly organized plan for achieving the goals we seek on schedule (Te.) When ISTJs go into goal-mode, their Te can make them seem like ESTJs, but most of the time they're just in Si mode, absorbing and categorizing every minute sensory detail of their surroundings and constantly adjusting their internal standards according to what is known.
Si says: If you don't know for sure, why risk it? We already have a tried-and-true method that direct sensory memory tells us will work, so there's no reason to change the method. Si likes to go by the book and stick to the known, that which has been directly experienced and mentally catalogued. ISTJs don't follow every stupid rule just for its own sake--that's an exaggeration of Si--but they will tend to automatically give more weight to any idea that remains within the accepted, traditional framework. If we wander too far outside the known, who KNOWS what might happen?
Honestly, I'm leaning toward ISTP for you...but you tell me which functional makeup seems to fit you better. Your apparent vehement dislike for following arbitrary rules and traditions just because that's the standard accepted method seems to indicate a high probability of ISTP.
