Jake the Snake
Jake's the dreamboat of the film, with his swept-back hair, dreamy eyes, and his wardrobe of plaid shirts and sweater vests. He's Sam's main squeeze, and he's made many young people swoon over the years.
But as we saw with the Geek, looks can be deceiving. And if you think about it enough, Jake is a big fat shady jerk.
What? Why do we want to shatter your dreams like this? Why do we think you should scratch "I <3 Jake Ryan" off all your old Trapper Keepers? And before you tweet us to death, please realize we're being extra hard on Jake here. He's young. He's still learning. And like everyone in the 1980's, he doesn't know any better.
But we really only see the bad sides of him in the movie. Plus, being critical is fun!
Here we go.
First, consider why he pursues Sam in the first place. Jake Ryan "doesn't even know [she] exist[s]." How does he find out? He sees her attempt to pass a note to her friend. He takes it, and he reads it. It wasn't meant for him, and he knows it wasn't meant for him. But instead of giving the note to Randy, the intended recipient, Jake Ryan reads it.
Here is his rationale for liking her in the first place.
JAKE: It's kinda cool the way she's always looking at me.
Jake likes her because she pays attention to him. Not for any of her own qualities. Simply because she feeds into his narcissism.
Secondly, Jake is a coward, especially compared to the Geek, who's always putting himself out there. Jake doesn't approach Sam until he is sure she likes him back. That kind of nervousness we can sympathize with. Sam's that way, too, after all. However, Jake wants to make sure he can get with Sam first before actually breaking up with Caroline. Sam is basically his Plan B, and there is no way he would have broken up with Caroline when he does unless he knew he could fill her spot with Sam.
Third, and most importantly, is how Jake Ryan treats both Sam and Caroline as objects. Sam is a goal to him, along the same lines as the birthday cake he gives her at the end of the movie. And Caroline—well, poor Caroline he literally uses as a bargaining chip with the Geek.
Jake "gives" Caroline to the Geek as if she's a human trophy. Women being used as rewards? What is this, Game of Thrones?
And what does Jake get in exchange for Caroline? Sam's underwear. He trades her for another woman's underwear. Reading someone else's mail has nothing on this level of shadiness.
To be fair to Jake, Jake returns Sam's underpants to her as a show of good faith. But we never see him reveal to her the fact that he read her secret note. If he's not being completely honest with her, his "love" for her is about as real as the cake he gives her. And from the production notes, we know that cake was cardboard. (Source)
It sure leaves a bad taste in your mouth.