1. Amazing musical numbers can be staged with virtually no effort or rehearsal time.
2. Despite complaining of a limited budget, expensive items like perfect costumes, props, sound equipment, and lighting are always available.
3. High school band members can play a variety of fast, popular songs perfectly, with no advance notice.
4. A Spanish teacher can devote all of his energy to an extracurricular club and never have to plan for classes, much less grade papers.
5. All teenage singers are fluent in every kind of popular music from the last fifty years.
6. High schools have exactly one to three very talented singers in each and every stereotypical group.
7. Teachers and students have boundless free time during the school day to chat in empty hallways, empty classrooms, empty offices, empty bathrooms, or busy but clean courtyards where nobody ever wears visible brand names on their clothes.
8. Audiences at all performances are quiet, focused, and appreciative.
9. Regardless of bad attitudes, heartbreak, family distractions, or any other problems, all students will pull through when it counts and perform remarkably well.
10. Every complex problem in life can be solved by singing a catchy tune that a young audience would recognize.
Gently Hew Stone 
Bitter a little?
I’ve only ever watched one episode of Glee (the one in which my cousin Aaron did the wheelchair stunts), but I’m astonished that I saw examples of almost everything on your list. My biggest beef? Number 2. They can’t possibly get enough money to get a handicap accessible bus to sections (or whatever it was), but they can pick up 12 high-quality wheelchairs (and I know a little something about quality wheelchairs) at a hospital TAG SALE? That sort of killed it for me, right there.
Oh, well. At least “Glee” afforded me an opportunity to name-drop my famous cousin. That’s worth something, right?