Interesting ravke.
My first thought reading your Q is that going to the positive is NOT my natural response. I have fought against my negative tendency for my entire life (and that's no exaggeration). While I dislike my negativity intensely, it is still a part of me. I may not like it ~ but it's who I am.
I think that part of this tendency is biological. I am treatment-resistent. Not just depression-wise either. My body is very resistant to anesthetics, anti-depressants, pain medications, etc. Most medications just cannot gain the upper hand with me. That is a huge fact of life for me. I'm not the only one who struggles with this resistance. Doctors reason that 1/4 - 1/3 of human beings are treatment resistant, for an unknown reason. That just has to be genetic. Maybe mutation of nerve cells. Either way, it isn't under our physical or psychological command.
Personally, I find that to be very interesting. (I'm a psych geek

I've got my BA. LOL!) That fact is worth studying, to see what the difference(s) is (are).