He needed stitches! Why did i laugh at that?!

Why do we laugh at seemingly inappropriate times? Descartes, Spenser and Freud offer theories which attempt to address elements of this question. Although their answers might lead us in the direction of understanding this phenomenon some of the most powerful examples to explain it might prove most apparent in our everyday lives.
Descartes claims that laughter can accompany wonder, mild hatred and of course joy. Why does in include hatred as a potential cause of laughter. This seems counter intuitive and inappropriate. Descartes writes that when laughter is rooted in this mild hatred that the cause is scorn. He claims that this is a mixture of hatred and joy with joy remaining in a greater proportion. At first upon reading this passage I struggled to recall a personal anecdote which supported this claim, until I thought back to approximately 15 minutes before beginning to write this post when I was silently chuckling at my roommates' uncleanliness. I was actually laughing out of mild hatred, or scorn (as Descartes would call it).
After this realization that Descartes might just have known what he was writing about all along, I decided to take a second look and try to match some of his scenarios to real life examples. I was met with significant success. Firstly in Descartes's "Article 179" which he titles "Why the least perfect are usually most given to mockery," I found a nugget of truth. This works in two different ways, in my opinion. First I remember that in my high school, there was a boy to whom I will refer as Ted. Ted was as close to a bully as any boy in the entire school. Because the all boys private high school was joined with its companion middle school which Ted and I had both attended I knew something about Ted that most of the incoming freshman (his favorite targets) did not. I knew that through middle school, Ted had been mercilessly bullied for his weight and myriad other pointless imperfections. He, as Descartes predicted was most prone to "mockery." (Descartes 24) To provide an example of this i recall a friend of mine, who is blind, and another who is dyslexic. Both of these people do not hesitate to make fun of themselves so much so that I have occasionally felt uncomfortable. These two people seem to wish to openly acknowledge their imperfections before anyone else gets the chance to notice or even talk about them.
Spenser in his discussion of laughter and humor offers a treatment of nervous laughter which is my personal favorite of the awkward inappropriate laughters. As a musician and competitive rock climber I have found myself laughing nervously before, during and after performances and competitions most especially when the all eyes are on me. At the most embarrassing possible moment....of course. Thankfully Spenser was kind enough to reassure me that I am not the only person who suffers from this psychological element of the human condition. Both he and Freud agree that this sort of nervous laughter is an emotional overflow valve. (Freud 111)
The only conclusion I am able to draw from this examination is that my initial assumption that these types of laughter are inappropriate was completely off target. These causes of laughter seem now to be perfectly healthy conditions of humanity.