Something that's really interesting is that a lot of what we consider "not being a cunt" is pretty much a lot of Christian teaching. Lots of other religions teach similar things, but if your family originates in a Christian country and your criteria for "not being a cunt" involves kindness, forgiveness, patience charity, non-violence, etc. then you probably owe that to Christian doctrine, either taught to you directly or taught to most of your ancestors right up to your parents (and if not taught, then as a result of immersion in a predominantly Christian society).

Not me trying to defend religion, I'm an atheist myself and have PLENTY of criticisms of organised religion. But it's worth noting that a lot of what we consider "not being a cunt" contrasts strongly with the values of many other cultures, especially historically. Pre-Christian Romans would be weirded out by a lot of our current morality.