Some consider themselves extremely lucky, but is there really such a concept? I myself work from a positive stance, and thus see the "luck" in most experiences, even if others don't. Still from a statistical viewpoint I am not luckier than the average human in the street.
Just like unlucky 13 is called superstition, lucky 7 is just as well. Superstition however is just a belief that has little or no basis in proven facts. One example is throwing two dice: it might give you the idea 7 is special, but that only comes up more often because two dice have more combinations that add up to seven: 1+6, 2+5, 3+4, 4+3, 5+2, 6+1. The chances of 6 for instance are less: 1+5, 2+3, 3+2, 5+1. And outcomes further away from 7 have even less possible outcomes.
Still, we humans see mostly what agrees with our view on life. If we consider ourselves lucky to be blessed with life lessons always, we learn even from the negative outcomes how to turn them around into positive experiences.