He has convolved luck with happiness. If someone believes he is happy, he is happy. If someone believes he is the lucky, he is not necessarily lucky. Seeing the world rose colored glasses does not make you any luckier, it makes you happier. By only asking for those that self-identified as lucky or unlucky, he has failed to isolate the variable of happiness. Here is an excerpt from the book which points out the author…
The point about perception of luck being self-perpetuating is good as well. If you view yourself as unlucky, you will tend to be more timid in situations where you might need a little luck to succeed, while a lucky individual will be willing to take more chances.
This dynamic is very visible in poker... After a run of bad luck, it's very easy to miss an opportunity to do something like play a drawing hand aggressively to make a player fold (I don't want to get the money in and lose, again!), instead taking a more passive, less successful route (I'll call the flop... of course, I missed again and don't have odds to continue, now I have to fold.).