In all fairness, the difference between real life and fiction is that fiction has a point. So alot of times, motivation needs to be emotional, logical and connected to what they're doing now when it comes to fictional characters.
But that said, it doesn't need to be that way with all characters. I personally loved it when Flash told Zoom that he didn't need tragedy to make him a better hero. People who do the right thing because it is the right are rare yes, but they exist in real life and fiction.
Honestly, I think it woulda been cooler if Barry was like that. Like Tim Drake, Justice or Nemesis (Tressor when well written). But honestly, I don't think Johns likes those kinds of characters. Tim's sense of justice was acknowledged by Johns, but never used and he pushed for Tom to be killed because he had his own Nemesis he wanted to use and didn't 'get' the current one (though I may be misremembering an interview there).