Here's an example of how we shape our own "personality types" which then shape us.
I went to bible college saying very strongly both outwardly and inwardly "I'm not a linguist." Why would I say such a thing? Well not on the basis of terrible school grades or any nightmare disputes with snooty French maitre d's. When it boils down to it, my problem is this: language learning requires simple hard work - learning declensions and conjugations and endless vocab. Basically I'd far rather invest my time finely tuning some doctrine essay than learn a list of irregular verbs. The pay-off simply seemed much greater. After all I'm a big-picture, artsy kind of guy. I'm not a linguist. (Note well the strong sense of a cultivated identity driving things).
So what happened? Well the indicative "I'm not a linguist" translated (as indicatives always do) to action. In this case: retreat from languages into other areas that I found naturally easier. So my efforts in languages were very ordinary. And guess what? So were my grades. So what did I conclude? "I'm not a linguist." These things really do become self-fulfilling.
Surely I should have been telling myself: "I am a linguist." The Lord has called me to be a teacher of His word and therefore He has equipped me to be the linguist I need to be. Whether I'll wow people with my brilliance in the subject is an entirely different (and irrelevant!) matter. The fact is, when it comes to languages no-one gets away without hard work and no-one gets to play their 'personality type' as an excuse to retreat from it. From the indicative of 'By the Lord's strengthening I am a linguist' ought to have flowed the imperative 'Be the linguist He's called you to be.' Instead I retreated into my type.
I'm fighting a similar battle at the moment with an extremely deep-seated self-identification "I don't do admin." Is this some morally neutral, hard-wired fact of my 'personality'? No, it's a sinful pattern that I've fed for years. Any help gratefully received.