The Tenth Commandment's focus on thoughts or feelings (and how could we actually distinquish sharply between the two in this matter)poses a significant challenge. As you note, how can one control one's thoughts?
Perhaps "control" is not the best term. Try substituting "discipline." Is it possible to discipline one's thoughts or feelings? Perhaps. Many of the classical spiritual disciplines are designed to reshape habits of the heart and mind, so that we might more nearly focus on God, the good or what have you. This being so, I wonder if the Tenth Commandment might intentionally break new ground, serving almost as a teaser, saying in effect: "Oh, we're far from done just yet. By the time you get to me, you're just getting started."
Both my children are bright. The tend to catch on to new things quickly. Still, when they were very young and I attempted to teach them how to relate well to others, I stressed actions. "Don't bite, hit, steal"--avoiding hurtful actions was the name of the game. As they grew, though, I shifted ground a bit. We could talk about the reasons behind our actions, why we do what we do. Guess what. Most of the time, we wound up talking about thoughts and feelings.
Of course, it's incredibly hard to discipline oneself. In fact, even the best among us falls far short of perfection. To quote Paul loosely, "We do not know sin until we hear 'you shall not covet.'"
To covet reduces us to a statement: "I want what he/she has, I must have it, I can not be happy without it." When we see this in another, or read it in cold print, we may be able to discern its essential silliness. It's another matter when we are the one consumed by the desire.
You're right, Rami. There is more to discuss. After all, Jesus talked a good deal about thoughts and feelings. Many Christians understand the Christian life primarily in terms of coming to grips with the inner self, so that both our actions and our interior life play out in the sight and under the grace of God. With reference to human society, the Tenth Commandment draws attention to a key contributing factor to human misery. All that--and we've not yet begun to discuss how to try to practice observing the commandment!