Explain luck

I have been trying the last few days to understand luck …
Luck, is something that do exist and could not be scientifically explained, some people are born lucky and others with bad luck, sometimes luck change but you can never explain luck.

Why some people are lucky?
Some people have luck behind them all the way, finding a good job, a good house, great deal on a car, finding money on the ground, winning the lottery … Luck follows them like a pet dog follow the master, while others have no luck or sometimes bad luck instead ….
My question is why?
I mean it’s not a matter of effort, because the unlucky guy looks for 10x more job offers before landing the crappy job, while the lucky guy gets an amazing job quickly …
It’s not a matter of goodness & personality, because many lucky people are arsholes while many unlucky ones are super nice.

I initially thought that each human have a package of attributes different from others but that have the same sum, like in video games, when you get experience bonuses to spend on your character, you can add strength, health, intelligence, dexterity … I though maybe at birth each human have a package of attributes that are different but have same sum, for example:
Intelligence + luck + health + creativity + communication skills + ….
And that when 1 of these factors is high, the others should be lowered …. But then i asked myself, what about people & kids that die in disasters … My theory don’t hold much.
Then i wondered if there’s a trigger that kicks on/off the luck, for example if this guy is lucky we could end up having a war in 10 years, so better give him bad luck … But again this theory don’t hold much, the same argument as before, how would poor tsunami victims have changed the future …

For me, i would like to believe that luck works loosely on the above theories, with other factors involved as well!