According to Google: Karma (Sanskrit, also karman, Pāli: kamma) is a Sanskrit term that literally means "action" or "doing". In the Buddhist tradition, karma refers to action driven by intention (cetanā) which leads to future consequences.
Seems most people aren't really sure if karma even exists and if people get dinged with it in their current life or will you have to pay in your next life? I believe it's actually a thing and that people seem to experience a bit of both.
For every action there is an equal opposite reaction. It's a proven natural law. Sir Isaac Newton's third law, actually! Newton was in my opinion was among the best scientists of all time. Some even said Einstein came a "very distant second" to Newton!
He dabbled in mathematics and the hidden laws that most don't understand. He could almost sense them probably due to him being a Capricorn with intuitive traits or maybe it's on account of the common known fact that he had Aspergers.
Maybe some people end up where they deserve to be based solely on how they were in their previous go around. I think most expect horrible people end up in a tough situation that would help them see the error in their ways by almost purging them from their darkness.
Instant Karma.. well, everyone has seen those videos on YouTube. The guy who was so terrible to the cat and the cat drops a vase on his head sort of thing. lol I mean it's almost a sinful pleasure when we see those types sadistic people doing those types of sadistic things live. It's like watching a train wreck and you just can't look away and then super hero comes along and saves the day . lol. It's like get your hand up in the air with your fist clenched and pull it in while saying "YES" type of moment!
Really bad people seem to always get away with everything but it always seems to catch up with them eventually and sometimes the more people they harm then the more to channel it to come faster. Or perhaps they actually see the error in their ways on their own and get themselves back on the right track after making a mends.
Personally I try to always follow the Golden Rule, which is, you do unto others as you would like them to do unto you. It's biblical, I know, but even if you are not really religious, you should consider following them, because if you do follow those base principals and God's laws you will go through life more positive and happy.
When I was in New York just the other month near central park we happened upon a school of ethics and I felt that would be a great place to attend or at least try and research it on your own if you didn't really want to even follow any religion.