First, you have to accept that concepts of good and bad may not be applicable here.
Queen Michael said:
I don't believe in karma, but karma's a funny thing. I've got a friend who believes in it, or at least used to (it's been a couple of years since we discussed it), and I pointed out that unless she's got some way of determining what actions the Universe considers good and evil, she's basically just assuming that her view of what's good and what isn't is always the correct one. Which I'd say shows a bit of hubris.
Pretty much that. So it's not you are good, therefore good happens to you, as good isn't objectively an easily definable category, but more like the same type of thing you do, you'll probably get, the "type of thing" being of course, obviously vague, which necessarily means that some people will find my conception of karma problematic (unprovable, undisprovable and sort of all-encompassing). Fair enough. More could be said but that would be too long, plus it would require me to do some serious research etc., so I'll leave it at that.
Second, the question comes up of how it works with reincarnation. The concept of karma in this life doesn't seem to be really working, as evidenced all around most of the time and I have never really been fond of the classical idea of reincarnation and even less of its simplistic interpretation in the way of you're bad, therefore you'll be reincarnated as an earthworm (because obviously being an earthworm has to be some form of punishment, right?). My take on this is to release reincarnation from the limitations of time. We're already deep into metaphysics as is, talking souls and cosmic balance and we steadily accept that reincarnation isn't limited by space, so why should it be by time? According to that, you could reincarnate in the past and maybe even in the present. I mean it seems difficult to imagine and it stinks a bit of paradox, I give you that, but just think of the consequences: it would basically mean that every living being that has ever lived, lives or will live are all just reincarnations of one and the same soul... (maybe that soul is god?) Suddenly, also, the vague idea of reciprocity presented earlier gets kinda obvious: you reap what you sow because in some reincarnation you are the one who's suffering the consequences of your actions. The notion of individuality and personality gets dissolved somewhere along the way, but dissolving individuality is something Buddhism has always been quite keen on anyway.
Taken like that, karma just means that whatever happens, happens. And through that balance is kept and that's just how it should be. And that's fine with me.