Our base instinct, as Humans, is always our most animalistic. Animals (which we are) don't really know what "regret" is.
The notion of "regret" is probably something Humans picked up during the Renaissance or some other faggy time period
What i'm trying to say is that "regret" and "sorrow" are just "made up" and we are just animals who are emotionless and just want to fuck and eat
hopefully, that will make you feel better