From my experience with how life works, we are definitely all going to pay for whatever we do in this life. If whatever we do is of good nature, we are definitely going to be getting positive returns from what we did but if we ever do the wrong things, then definitely we are going to suffer the consequences of our wrong doings.
It's even written in the holy Bible if you are the religious believer type of person, you would be very aware of the words in the holy book. Evil never goes unpublished, so whatever you do to your fellow men and if it's an evil deed, you can be rest assured that such evil would behalf you.
There is a part of the written proclamations that the sins of the father's shall be visited upon them and their children's children. So, nemesis is 100% real and I believe in it.