As established elsewhere, amnesia comes up a lot in TV. Amnesia is a funny thing in the real world and can give you lots of strange symptoms. In TV, it's very weird too, but it's much more specific.
According to most of the religions if a person did good deeds (Karam) in previous life then one lives good life now and if one did bad Karam in previous life one suffers in this life.
When Bob dislikes Alice, he may call her funny names. Of course sometimes Bob is actually just a Cloudcuckoolander, and not actually being malicious. There are many different ways to do this and variations on how it's done in fiction…