In principle, gratitude is all about attitude. Gratitude is a choice we make to see good in ourselves, our situation and the people around us.
Discontent arises in me when there is a gap between what I have and what I want. When the gap is large, I am apt to try to close it by getting what I want. Advertisers know this, so they breed discontent. They try to persuade me that what I have is not good enough, and if I just had more and better stuff, I would be happy. Similarly, I am sometimes seduced into thinking that people around me are not good enough and that if they would just change their behaviors, I would be happy.
It is okay to want things to be better, but it is not okay to put down ourselves, our situation or our group in order to justify selfish behavior. A person lacking gratitude is likely to be a drag on good group decisions.
Sometimes getting what we want leads to happiness, but the surer way to close the gap of discontent is to look with gratitude upon that which we already have.
Practical Tip: Take stock of what you have and see the good in yourself, your situation and your group. Imagine how things could be worse. Reach out and help someone less fortunate. Say thank you.