It's a beautiful thing to have lungs that allow you to breathe air and legs that allow you to climb mountains, and it's a shame that sometimes you don't realize that that's enough.
Our happiness not only depends on the nicer aspects of life but also on our ability to make peace with disappointments. People often disappoint us, so does life. Making peace with disappointments does not mean we submit to whatever is wrong or unfair. It simply means we take responsibility and give our best to improve the situation, knowing that the outcome is not in our hands.
In the face of these disappointments, we learn how to look at whatever we feel is wrong as wrong and yet don't judge the people or life in general, if we can also appreciate the goodness, we can be fairly happy.