If only Dawn or Ozzy or someone thought to give Cochran more reassurances.

Dawn or Ozzy could have made the move of conferring II to Cochran at Tribal so he would have had no more worries about drawing the rock, but of course that didn't happen.

Cochran's insecurities are central to how he is perceived by others. While it is good he has self-awareness of his limitations, his tendency to dwell negatively on them is self-defeating. The smart player would be trying to play on his/her strengths while diminishing his/her weaknesses. That first day when he went ahead and stripped down to go frollicking in the surf, that was a great move, the sort of thing he should have kept doing.

Unfortunately, an inferiority complex is exactly the sort of thing that attracts bullies, so I've no doubt Cochran has put up with a fair amount of getting picked on throughout his life. (And outside of bullying, it can also become a source of frustration to friends and family, negativity is such a buzzkill.) Cochran is still in school though, still maturing and coming into his own, because adulthood isn't a 21st birthday present it is an ongoing lifelong process. Survivor just isn't a very good place for growing up.