Then what is that "luck" which everyone around us talk about ?

To me it is our good deed, it is our karmic account not just of this life, but life after life and these stored karmic account reflects in our life at some point of time and in different births. Some people borm billionaire and some just as poor as they have to work even at the age 4 or 5.

This entire dynamics of life is so complex that it is difficult to understand. So many mathematics, physics is going on in this Universe every moment and that also affect our mind to a great extent. In this world human being is free to do any thing, but the result does not yield as per their will or wish.