Why do we want the things we want?

Why do we want things that we know we can't get? Or is it because we know that we can't get those things that we want them so desperately? And if, by some miracle, we get those things, will we still want them with the same passion? Maybe not, especially if the "ungettability" of the object was what had made us want it. Imagine a kid who creates a ruckus in the supermarket when he wants a toy that his parents are refusing to buy. Now, two things can happen when his parents agree to buy it. Situation 1: The kid will love the toy and cherish it forever. Situation 2: The kid will lose interest in the toy soon and start hankering after another one. One can never guess how much he will want a thing after he gets it. And, this is not limited to inanimate things alone. Think of love marriages. Why do so many of them fall apart in less than 5 years of marriage?

Anyway, I wish there were an instruction booklet that would help us decide whether we are desiring something because of its obvious unattainability or whether we genuinely want it for the rest of our lives. But, unfortunately, life does not come with an instruction booklet. So, I guess we will just have to continue desiring things believing that we want them for the rest of our lives. And, let's hope that if we do manage to get them, we will continue liking them with the same passion. However, after getting them, in case we realise that it was just a passing fancy, we will have to learn to move on to other things without trying to force ourselves to like those things. Because - let's face it - you cannot fake passion for long without being terribly unhappy. On the other hand, if we do not get the things that we desire, then how long should we wait before accepting that it's "never gonna happen" so that we can move on or do we foolishly continue to tell ourselves "never say never"? I guess we will have to cross that bridge when we come to it. And, isn't this very unpredictability that makes life so interesting? Either way, we will have to believe that what we did not get was probably not worth our time and effort. Life is way too short to be spent on regrets and what-ifs.