In my opinion, happiness is a state of mind where nothing is harming or upsetting you, and it depends on every person's life experience, history, thoughts or even wishes. When you feel acomplished. When no bad emotions are bothering you. When you feel relaxed among with the things you love.
Is happiness a state of mind, that we can easily reach?
No, since we have many challenges in our lives.
I think happiness is a goal we usually try to reach, but is it possible to reach this as a long-lasting achievement?
I think so. I always keep hoping that it happens.
Is happiness related to the country we live?
Somewhat. As I said, it depends on every person's life experience, history, thoughts or even wishes. Some may like it, some may not.