The key is to consider what "discontent" really means. And not only what you mean, but what does one do when they're discontented?
It seems, and spiritual teachers throughout millenia have said so, that our natural state could be called "contentment". That is, our natural state is being pure essence, having an experience of unity with all beings. Discontent is when we interfere with that natural state, and indeed we tend to interfere with it constantly hence few of us have experienced that unitive consciousness because the vast majority of us are constantly interfering with our contentment.
I think the typical person might think "discontent" means an angry person, one who's about to "go postal" or start foaming at the mouth like a raving lunatic. Those people are clearly discontented about something, but it's also clear discontent takes many forms. What about when you're driving and irritated at the other drivers? What about the line at the grocery store that takes forever? Discontent ranges from mild upset all the way to the raving lunatic.
We have many words to describe the forms of discontent ... like "snippy", or "ticked off", or "irritated", or "annoyed", or "henpecked", or "enraged". But they're all describing the same principle, our experience of our natural state is blocked.
Now, what do you do with discontent? In other words, if discontent is to be the first step in progress, how can you take your discontent and make progress with it? It seems that if your discontent leads you to violence, you probably aren't making "progress".
What is "progress" here? I'd suggest it is to take steps towards allowing ourselves to experience our natural state.
The trick is to know what our natural state is. It seems that most people have rarely or never experienced that natural state of unitive consciousness. If so they may be thinking their discontent is their natural state. So if they were to experience unitive conscioussness, would they recognize it?
For example some ancient spiritual traditions use hallucinogenic drugs (e.g. Peyote) to reach unitive consciousness. That is, it's a part of their spiritual practices, and their spiritual practices are meant to lead people to experiencing their natural state of unitive consciousness. But when Peyote was brought to modern american culture it became a party drug. These people may have had unitive consciousness, but didn't recognize it and simply got off on the wild "high" the drug gave them. Sigh.
But this points us in an initial direction to take. There are many spiritual practices where one can experience unitive consciousness. My current favorite is chanting divine names and words.
As you go along in spiritual practice it becomes necessary to begin looking at the parts of you which have discontent and are hiding your natural state of unitive consciousness. This is a part of Buddhist and Shamanic practices, and are probably a task undertaken by anybody who wishes to undergo deep spiritual transformation. I took extensive training with the Barbara Brennan School of Healing, and at BBSH they call this the "awakening process".
Where does discontent come from? That's a good questions, and reams of books have been written about this. I believe it comes from the ego. "Ego" can be read as "easing god out", but it is a process we humans have of believing that we, our selves, know better than god how to run our lives and make decisions and how to live. I'm beginning to see the folly of that belief. If the consciousness that is "god" created the universe and everything we see, don't you think god's consciousness might know a few things about living life?
So, I say, shake off your ego, shed your discontent. All you have to lose is your suffering.