When someone who you were supposed to be with together in an endeavor, for example, your classmate, suddenly calls it quits, says "it was no longer worth the trouble," and then drops out, one could not but feel a sense of betrayal. Aside from the sadness that his absence may bring (yesterday he was just here beside me); beyond the uncertainty of seeing him again; and, worst of all, more than the puzzle which he leaves on his trail (why did he go? what were his reasons?)--what his departure ultimately means for you is the realization that it is possible to quit and leave, that you too can go.
We get caught up in the details of everyday life usually forgetting why things are done and why they are done in such and such a way. The student forgets what education is for: he only knows that everyone is studying, that it would make him different from his friends if he did not (work already, study at home, etc.); and that the only truth you hear about it is that they say you will get a better job (which translates to better pay) if you finish your education and finish it well. Then lo and behold, see how the graduate finds out that in his first few jobs, because he did not pay attention to the essentials of education in favor of memorization and specialization, he has to learn, always the hard way, the basics which he failed to practice: discipline and diligence, humility and integrity.
And so when you do not know what your being a student is for, when you're only pantomiming what true students are, mimicking them at the same time mocking their seriousness, it becomes rather easy to leave it all behind: all you need is a failing mark for a test you studied for all week or a depression which would not go away and you already have all the reasons to leave because you had none to stay. It is the same with the lover who departs and the suicide.