honestly, looking back when i was in freshmen to junior (currently a senior), i don't think high school itself, as an institution, was all that bad - indeed, i had a couple of awesome teachers and got to know a few friends i'm still in contact with today.
what sucked far more than the institution was, well, me. i wasn't in a good place psychologically or even physically at the time, and my socialization was pretty poor for the most part. i think this is the real source of many people's hatred of high school - adolescence is a difficult time no matter who you are or where you are, and the place where you are when you go through these emotions can result in some negative associations. Now that i am graduating. i am sure gonna miss my high school years.