When I saw the first episode of "School Days" I thought to myself, "This is a typical high school scenario, it's sweet and happy". However towards the end of the first episode i realized "holy crap, this isn't going to end well". As the series went on I found myself feeling frustration, anger, and overall the feeling of wanting to punch a douchebag in the face. At a certain point I wanted to stop watching this series because the main character would be bangin a girl one after another. I was getting really fed up with how he acted, but I figured i shouldn't half-ass it, so i continued.
At the end of the series, i found myself disturbed, yet at peace because Makoto got what he deserved (YES!). I also was unable to sleep because of the fact that this can be high school drama at its worst in some twisted world. I found myself hating this series, but i started realizing, no other anime i have watched in all my years has made me react in such a passionate way.
In conclusion, "School Days" is a must see anime, and will go down as one of my favorite, and most hated anime's of all time. I highly recommend watching it.
WARNING: this anime is not for the feint hearted.