Do you know anyone who is not seeking more peace and contentment in their lives? Unlikely. And in many ways the term serenity best encompasses this concept.
Practicing non-attachment is difficult if not impossible for most of us. What does it actually mean anyway? Perhaps it refers to the obsessive, even neurotic belief that we can change others, make decisions for them, prevent them (and ourselves) from suffering in the end.
What I have observed is simply this–people who seem content live in a universe of their own in which their suffering seems somewhat limited and controlled. They understand the rules of the society in which they inhabit. They are comfortable with their associates and their environment. They are not seeking radical change, nor are they unhappy or in conflict regarding the conditions of their lives.
These people may live under circumstances that others might even find intolerable–trailer parks, low income, small towns without the cultural, culinary, intellectual sophistication of large cities. And yet they may be more content that a more affluent city dweller or suburban dweller who is never satisfied with the state of their existence.
Very often serenity is associated with our personal connections with others. Loneliness sucks. On a primal level, we all need personal interactions with human beings we feel comfortable being with.
There is the stereotypical example of the overtly wealthy couple with enormous material possessions who remain miserable because they cannot "keep up" with their even wealthier friends. To outsiders this seems completely absurd. Yet serenitiy is an inner subjective perception. If individuals inhabit a universe which doesn't quite fit—they suffer.
I believe that it is possible to "feel" your way into the universe that suits you best. Be truthful to your own values. Be honest and introspective. What do you need to make you happy or serene. It will be unique to you. Don't "borrow" someone else's universe. You won't fit in.