What with the group being so Hipster, it might seem strange that Patrick is so into football. Then you think ok, maybe he's just there for Brad. Or maybe he's appreciating the only place where he can openly, vocally, and as loudly as possible give Brad all his support.
The group ignoring Charlie after the incident with Sam. Note how easily they accept him back after he defends Patrick. It's likely only Mary Elizabeth hated him and they avoided him for a while just to avoid setting her off. When he defended Patrick and Mary Elizabeth found someone else, they had nothing to fear from her.
Mary Elizabeth developing an interest in Charlie. Her next boyfriend is someone she likes because he's opinionated. Note that her first real impression of Charlie is his Brutal Honesty when he tells her she'll be quite the fashion victim in a few years, and when he bluntly says she likes to boss people around. She admired him for telling it like it was.
If you first read or saw this when you were a young teen, you were probably already sad/horrified when Sam reveals her first kiss happened with her father's boss when she was only eleven years old. Then you reread or rewatch some years later... and realize the abuse almost certainly didn't stop there.
In a meta sense, we see Patrick pretending to be the shop teacher before he comes in, with Patrick mentioning Vietnam as a part of his jokes. It may seem funny, until you remember that Tom Savini, who plays the shop teacher is an actual Vietnam War veteran who experienced the horrors of death from the war in person.
It's really that hard to find out that "the tunnel song" is David Bowie's Heroes? I mean, sure, pre-internet era and all, but didn't any of them try going to a record shop and quoting the damn lyrics?
Becomes Fridge Horror a few years later, when this song that means so much to them becomes a freaking Microsoft ad.
They were high at the time weren't they? Plus pre-internet era meant that if you didn't own the CD or cassette, the only way you'd hear the song is if it played on the radio or in a movie somewhere. Besides can you remember any lyrics from a song after you've only heard it once?
Well, apparently it was not a big hit to begin with and only got famous later. Still, any self respecting cool kid with killer music taste will recognize instantly that it's Bowie singing. After that it's only a matter of remembering how it went 'we could be heroes' over and over again and then finding the track called Heroes on the album called Heroes.
A case of Reality Is Unrealistic: the author based it on something that happened to him as a teenager in the early 90s, since the song only became popular later.
Another thing to take into account is that the "tunnel song" being "Heroes" by Bowie is for the film (though still featured in the book if this troper recalls correctly). In the book, "Landslide" by Stevie Nicks was the "tunnel song". And seeing that the writer/director of the film happens to be the author of the novel, he decided to change the song to something that would be more emotionally fitting in that moment than keeping it thematically fitting (as "Landslide" uses the line "time makes you bolder, children get older and I'm getting older too", which would work even more-so for the end of the film). Even with that, the creator of this story chose to change the song but kept the original premise that they didn't recognize it because it's a setup that ends up being paid off at the end that he didn't want to change that part of the story. It just boils down to the author making a creative decision to change one song without it completely affecting the overall story.
