Then there are those characters who are high achievers. I'd be surprised if their success doesn't trigger resentment. Again this could be for comic effect but I can see tragedy emerging. What about those who are used to success but fail this time?
And as for those lower down in the chain (i.e. those with ambitions but no chance of meeting them), how do they react when it seems that everyone else is getting the luck and there seems to be nothing left for them?
Naturally these things are all a great test of character in themselves as well. The only thing for any writer to beware is to watch you don't unwittingly reveal more of yourself in the way you write characters!