It seems to me that everyone has natural preferences for their lives. If you really observe people you can clearly see that they do the most mundane tasks in different ways.
Since most people don't suffer from self-consciousness, it is safe to assume that we do these "simple" tasks without even thinking about what we are doing.
Unless you implode your body with drugs and alcohol or your brain does a self-destruct in anger or fear and temporaily changes the ways it thinks, I think we cannot change most of our personalities.
I have tried being rebellious, logical, and perceiving only to wind up depressed, tired, and clueless. I simply find imbalance in disobeying rules and creating massive conflict with others.
I am sure that if any INTP attemped to become an ISFJ, they would have the same type of problem. It isn't possible to change yourself.
Call it God, call it nature or nuture, but whatever the cause, our brains work in different ways and their processes are cemented thick to prevent tampering.
If there is a way, tell me, so I can get rid of my F once and for all.
Otherwise I think we are seem to follow a straight line in which we are engrossed with our ideas, thoughts, actions, and behavior. This trend line is the DNA that makes up our being.
I have recently had success with using my Extroverted Feeling dominant function. I have not only opened up and became more extroverted, but I feel a extreme energy inflation. With this energy comes happiness and vigor.
Do other types have similar experiences when they use their dominant function more often?
And does using more natural energy = or create Happiness?