in my opinion we should not blindly believe in this theory in order to treat ppl in a good way, but follow the other theory which says: "Do good deeds and throw it in the sea" so if someone appreciate well and good, if not you will appreciate your self coz this is what it is supposed to do.

now for the bad deeds also we shouldn't prevent ourselves from doing it just coz it will have the karma effect and it will harm us back in someway, but we shouldn't do it coz we are not supposed to do it and that is all.