Why do people who have faced the worst in life often seem unafraid of death?

Can you stop being envious of someone just by deciding their lifestyle isn't actually for you?
How does understanding a narcissist's motives behind their lies give you an advantage in dealing with them?
What is it called if one person with additional needs gets laughed at and bullied, by a group of them but other people who are similar don't?
Why does a low compatibility score often fail to predict the actual success of a marriage?