The title of this post is a paradox I've understood since I was pretty young. I always related it to the challenges of being in a relationship, but it has some applciation to an individual's life as well.
It's pretty simple, really. When a couple is working together towards a goal or trying to fight a common battle, they're a team. They support each other, thank and congratulate each other. They are focused on externalities. But when there are no externalities, there is nothing to fight but each other. There are no goals but their own individual ones. They become competitors. There is nothing to blame for their unhappiness but each other. An external conflict masks an internal void.
For an individual, it's similar. A life of misfortune - starvation, armed conflict - seems to teach people to focus on the good. It suggests that the very contrast between beauty and wretchedness makes beauty all the more powerful. A person with every advantage has no such touchstones. They can only blame whatever discontent they feel, whether large or small, on themselves. In this case, though, I want to say that an external conflict fills an internal void, letting in both the good and the bad, making a home for the whole world inside a person.
To feel love is to feel pain, perhaps.
If you can handle peace, I think you can handle anything.