Karma, in the sense that it's most often used these days ("if you do something bad, then something bad will happen to you in return") doesn't really exist imo. It's just that when you know you've mistreated someone, you start feeling guilty and obsess over it so you interpret all the negative things that happen to you shortly after the incident based on that.
In reality, negative things are inevitable and happen all the time (and, from my experience, mostly to people who don't deserve them). They don't happen because you've also done something negative yourself. There's no connection
Kind of. I don't think karma happens because of a spiritual force, but because ignorance makes you do dumb things, pettiness turns other people away, etc. Doing bad things will inevitably put you in bad situations.
