The conclusions section is the other end of the pole. One of the basic ingredients of good research is to be able to acknowledge one's own short-comings (note: is it not true for life as well - being able to identify our own mistakes and short-comings?). Therefore pointing out open issues in your model / framework / experiments in the Conclusions section is of utmost importance.
One of the primary reasons I took to research was because I wanted to contribute something to the world holistically. It is an endeavor which attempts to make our lives better! As I read in one of the papers today about the impact of social networks research:
"Social network analysis is useful for the development and self-optimization of the society as a whole."
The paper was published in the renowned scientific journal Nature and therein comes its wide dimensions of contributions!
Indeed, this is the kind of contribution I want my thesis to make to the world! Trust me, paper-writing comes with a lot of insights into oneself - not only the thesis topic, but life as a whole. After all, as someone once said (when I was starting off my PhD), "research is similar to being in love, a relationship, a very serious one, a relationship that needs time, effort and commitment: commitment for the lifetime..."
I guess it is true and I will make sure there is no dearth of commitment anytime; a personal trait I have always cherished in myself; commitment to whatever I am serious about. Probably not everything has worked out positively even after this, but I am truthful to myself: that I tried to the best of my efforts ... :)
And yes, if you think I am totally brain-washed about research or commitments in life, then you are right, I am :)