Shows on Nick are made to have fun, not so they would really show you the life of teenagers in Middle School. For god sakes, don't pick on every little thing you see wrong with the show. It's about three friends and about their ups and downs at school. I'm not saying that I completely love the show, because some episodes weren't that good, but I'm not saying I don't like it either.
Again, Nick has shows that are just made for fun. Ned's Declassified School Survival Guide, Zoey 101, Unfabulous, & Drake and Josh are for those people who want to have fun watching a show about a imaginary place. If it showed really was middle school was like.. well then it'd be boring and uncreative.