Luck is defined as events occurring by chance rather than by one's own actions. In this matter, I agree with b_b that you need talent, drive, hard work, persistence, and more talent but you can have all that but not be in the right place, not meet the right person, be on the wrong train and so on -- the inexplicable je ne sais quoi --

I completely agree with you, based on that definition. But what mk and I were referring to (I think) is the definition of luck as a thing that people possess. The common way of talking about luck. Jack did something good, he must have luck on his side. As if says something about his future, as if he has luck instead of luck happening to him, the definition you describe. It often negates any effort someone did to achieve, with people brushing it off as lucky. That irritates the hell out of me.

It took a favor of statistics to find hubski -I happened to scroll all the way to the bottom of a /r/TheoryofReddit post, where someone posted a link here- but I wouldn't call myself lucky. I'm not gonna have a better chance at finding good sites because I found hubski. The opposite is more likely, because of regression towards the mean. When luck helps you out greatly, you are more likely to not experience luck right afterwards because luck as you describe isn't that common.

The only common known luck I enjoy is that sung by two French DJ's and Pharrell.