Why is Don Quixote (First book) viewed as a tragedy by some people? Explain, and use references.

On many levels, Quixote and the book for which he is named can
be seen as a tragedy.  I think that there are a couple of reasons for this.  The first being that
Quixote's quest is unrealized in reality.  In the end, Quixote's voyage and purpose to honor
Dulcinea, live the code of the knight, and bring justice to a world lacking it are elements that
are not fully realized.  While Quixote is fully confident in what he does and self assured in the
value of these elements, they are not values that the world embraces as transcendent.  In this
light, there is a certain tragic condition in Quixote the character and book.  There is a certain
level of sadness and tragedy in how people take advantage of him and how his sense of self,
something so pure ends up being manipulated and discarded.  Quixote aims for the stars and
crashes to Earth, full of bruises and scratches.  There is something tragic and sad within this
vision.