I think one of the things that affect people also is not that they don't really have potential or didn't realise the potential itself but they lack people or environment that will help them live upto the potential
That's an interesting way to put things up... I could say for myself that my main excuse was (and sometimes it is still) that I was living in a bad country, that didn't give me a chance to succeed... In the end, that is just another excuse, as if I was enough ready, or aware, I would find the way to succeed, or just leave and change the environment... Unfortunately, in my example, I made a change 10-15 years later than I could...
In some way, I waste my 10-15-year potential due to my insecurities...