1. All the kids are 25
Have you ever noticed in just about every tv show especially where high school are featured, the "kids" look 25, because they are...actually 25. They may shave and try to put them in juvenile clothing, but muscle mass, wrinkles, 5 o'clock shadows, and reality tend to betray the idea that these "kids" are anywhere near the age of 19 or less.
2. 30 minute break times
I'm sorry, but when is the last time that in between Period 1 and 2, you had time to go find your six friends, talk about the game last night in full detail or some boy you like and if he liked you, then go answer a few texts, then eat a snack, and then 30 minutes later...apparently...you are needed in your next class. Whhhhaaaaatttt? At most, most kids have 10 minutes between classes to mad dash to the bathroom and their locker before trying not to be late for their next class.
3. No one ever goes to their "one" class
I'm looking at you Buffy, 90210, Teen Wolf, Twilight, The Secret Circle, Vampire Diaries, Riverdale, etc, etc. It's like they introduce the one teacher for the apparent one class that is required for the students, and then for the rest of the season you only ever see them show up to school, something happens, and then they are never in class again or they go to class and then leave and no one questions why they've been gone so long or they just don't come back until mid season or never in a movie.
4. Teachers come to your house or meet you outside of school
Um, unless the show was about some teacher doing some illicit things with a student, when would it ever be appropriate for a teacher to show up at a students house, or drive them home, or pick them up from home if not sanctioned by the school and with a permission slip for the exact reason you're now thinking. I once had a job working with kids, and one of the assistant staff got fired for driving a kid home who happened to live in the same apartments as he did. He thought he was being nice b/c the kids parents were super late and he knew them, but you can see why the school couldn't take that kind of crazy risk.
5. Everyone participates in everything enthusiastically
Have you met teens? Who is excited for everything all the time? A third of students are half asleep, another third marginally care what's going on, usually if it involves their friends, and the other third, are excited and show up with grins and energy.
6. Food fights exist
I'm pretty sure our janitorial staff were ex-militia fighters somewhere the way they appeared suddenly around corners and would glare at you, so the thought that we could all just get up and start throwing around food, and it would all be some funny cool joke and the staff would be awesome with that, is the furthest thing from reality. A food fight would have meant suspensions or expulsions for any student, or any type of fight for that matter. Written clear as day in the student conduct code.
7. Student fights on campus
There is no doubt that student fights happen on campus. Just go to youtube, however, when you see scenes where like the whole school is practically there and gathered round and the fight just happens for 20 minutes uninterrupted on school campus, is ridiculous. There are teachers, staff, and nowadays, campus cops and cameras everywhere. A fight could happen, but it's not going to last that long without intervention from one of these entities, and you get caught, you're both going down.
8. Everyone is only allowed to be part of only one clique
A lot of people do hang with a certain clique more than others, but many kids are part of many different activities, so this idea that the cheerleader only ever hangs with the cheerleader and no one from like the band geeks will let her into their circle is stupid or the jock can't be with the drama people, stupid.
9. Every single teacher and principal and staff member is mean
At my school and many others, a lot of the staff were nice people including the principal, sure if you were an actual trouble maker, you're not going to get them on their happy side, but a lot were really good educators and only wanted their students to do their best and to help them get into college.
10. What about college
My junior and senior years were 80% spent on trying to get into college. Taking this or that class, filling out apps, visiting schools, testing, trying to pass all my classes with flying colors. Apparently on tv high school, this process takes like 2 minutes on one episode where they just fill in the app and then wait to hear if they got in.
-everyone's problems are solved by the end of the movie/tv show
-the geeky girl/guy takes off their glasses, and are suddenly hot and every person wants them
-everyone at prom knows how to dance the exact same moves to the song everyone knows and they do it with perfect choreography; they also all know how to sing perfectly
-no one is ever caught drinking/doing drugs or is ever strung out/drunk with any consequences
-house parties take over the entire block and everyone at school is invited
-the outsider always ends up with a great group of friends by the end of the movie
-even if the jocks are losing all season, they pull it out and win by the end of the show/movie
-no one has parents and if they do they are in no way involved in their kids lives to the point where someone may need to call CPS