It is probably true that the "lucky" person has a positive attitude. The person who says: "I am so unlucky, I never win anything" probably does not enter as many competions, gamble as much or buy as many lottery tickets as the person who thinks they are "lucky".
All luck depends on chance. A person may flip a coin 10 times and it could land on heads every time. Flip a coin 100 million times and it won't land on heads every time (if it is fair). It landing on heads 50,000,010 times would be unremarkable. "Luck" does even out in the end.
