One way to look at "cogito ergo sum" is as an interesting intellectual thought. But Descartes clearly indicates that he actually had this thought in winter 1619 under very special circumstances:
I was then in Germany, attracted thither by the wars in that country, which have not yet been brought to a termination; and as I was returning to the army from the coronation of the emperor, the setting in of winter arrested me in a locality where, as I found no society to interest me, ...
Considering that he published the discourse many years later in 1637, I wonder whether this thought wasn't some sort of enlightenment that actually happened to him. But the only way I see how such an abstract thought could actually be an enlightenment, is if he really was in a state were everything was questionable to him, perhaps even his own existence. (The situation he describes seems well suited for developing depressive symptoms, and the 30 years of war that followed certainly were depressing.) What also strikes me as odd is the way that Descartes describes his method as something personal:
I have never contemplated anything higher than the reformation of my own opinions, and basing them on a foundation wholly my own. And although my own satisfaction with my work has led me to present here a draft of it, I do not by any means therefore recommend to every one else to make a similar attempt.
Here comes my question: Many of Descartes thoughts have been taken as "obvious truths" by laymen, but have been deconstructed by philosophers as very questionable. But at least in "Discours de la Méthode", they are stated as something personal without claiming undeniable truth. Is it generally considered that this was just a rhetoric trick of Descartes, or is the interpretation of "Discours de la Méthode" as a personal account also common?
EDIT The above question arouse from the following experience: When somebody praised Descartes' thought "cogito ergo sum" as the supreme achievement of human intellect, I once replied: "How deeply do you have to be disturbed to question your own existence?" A historically and philosophically more literal person then suggested to us that we should take the circumstances of Descartes' time into account when discussing his thoughts, especially the Thirty Years' War.