Our our worst enemy sometimes is ourselves. We limit ourselves by playing games in our head. The examples you used is an illustration of cognitive dissonance where you want to do well but you talk yourself out of it. I agree there would be not everyone can be a doctor or architect and it doesn't come easy. Too many people are looking for short cuts in this world. You have to stick it out and have grit. Life is a grind and if you want to be successful you have to keep pushing forward.