There is a genetic component so I'm guessing most of us are probably hard wired towards a more sensitive nature but essentially from what I can tell most of us grew up in less than appropriate environments that didn't teach us how to properly express and control our emotions and so like cboxpalace said we learned our own coping mechanisms for the bad hands we were dealt.

Unfortunately when thrust out into the real world our coping mechanisms don't mesh so well with other people and so we need to learn all over again how to deal with things.

Basically, from my point of view emotionally we are still children, still trying to learn what most others learned earlier in life.

And that's how I think we help ourselves we try to identify our less than healthy attitudes and we learn how best to work with what we have.