Character Analysis
Odd Man Out
Brian (Anthony Michael Hall) has the misfortune of being the Nerd Stereotype in this story. Even though everyone else pairs up at the end, Brian's left alone—and he has to write the essay explaining "who they think they are" for the others, while they all skip the assignment.
Hughes—who probably identified with Brian to a fair degree—was just trying to be realistic when he wrote this part. Having Brian pair up with Claire would've seemed like fantasy wish-fulfillment to audiences. (But what about Allison? Wasn't she in Brian's league?)
So, this dude winds up with the short straw. But he also learns a lot and pens a manifesto. Maybe that's breaking even, eh?
At the beginning of the movie Brian articulates the lesson he—and presumably everyone else—has learned:
BRIAN (voiceover): Saturday, March 24, 1984. Shermer High School, Shermer, Illinois, 60062. Dear Mr. Vernon, we accept the fact that we had to sacrifice a whole Saturday in detention for whatever it was we did wrong. What we did was wrong. But we think you're crazy to make us write an essay telling you who we think we are. What do you care? You see us as you want to see us—in the simplest terms, in the most convenient definitions. You see us as a brain, an athlete, a basket case, a princess, and a criminal. Correct? That's the way we saw each other at 7:00 this morning. We were brainwashed.
By the time, the movie ends, they've realized that each one of them is all of the above— a brain, an athlete, a basket case, a princess, and a criminal. They all can relate to each other's experiences. Or, at least, Brian's realized this—since he wrote the essay.
Revenge of the Elephant Lamp
When we first see Brian, his angry mother is needling him to do homework while he's in detention and not waste time. Brian has to deal with this kind of academic pressure constantly. He tries to explain he's not a huge fan of his parents, but Bender argues that his parents are worse:
BRIAN: [...] I don't like my parents either, I don't... I don't get along with them... their idea of parental compassion is just, you know, wacko!
BENDER: Dork...
BRIAN: Yeah?
BENDER: You are a parent's wet dream, okay?
BRIAN: Well, that's a problem!
In fact, all this pressure to be a model student is the reason why he's in detention in the first place. As he reveals later on, in a tearful speech, he flunked shop class after he built a lamp that didn't work—the lamp was supposed to look like an elephant, and it would light up when you pulled the trunk. But Brian accidentally built a non-functioning lamp: pull the trunk, nothing happens.
This totally messes up his GPA and jeopardizes his chances of getting into the very top tier of colleges. So he brings a flare gun into school intending (apparently) to shoot himself with it. But the flare gun goes off in his locker, leading him to receive detention.
So, it's a peek into just how pressured Brian feels, to put it mildly—he's been penned into this academic, grade-obsessed lifestyle, yet he hates it. He doesn't like the way he appears when he's locked into this hyper-competitive academic mode. But the tension between who he is and who he's expected to be causes him to make this half-baked suicide attempt.
The other kids finds this concerning at first—thinking Brian intended to kill himself with the gun—but amusing when they find out it was a flare gun that accidentally went off. Brian has to laugh too. So, thanks to all this academic pressure, he's managed to look pathetic and ridiculous and kind of crazy all at once—remember, all that Bender's in detention for is pulling the fire alarm.
So, in the end, Brian's explored his emotional issues, smoked marijuana with Bender and the others, cried in front of everyone, written everyone's joint-essay for them, and failed to get with either of the girls. But the human insight he's gained is what's really important, right? Maybe?
Brian Johnson's Timeline