Why doesn't Bender just drop out of school instead of show up to detention in the first place?

He's also not stupid, and probably understands that he'll need a HS diploma to obtain even the most basic job in the future, which I'm sure he believes himself destined for because of his horrible upbringing by parents that make him feel worthless.

Plus, even though he hates school, he is probably in no hurry to leave it. Right now, it's the one place he can go and be around his friends and escape the misery of his home life.

Just a act and I think he was selling weed in the place also.

Just a act and I think he was selling weed in the place also.

"He clearly hates school, he doesn't seem to have parents who would care if he did drop out, and he doesn't seem to want to go to college anyway. "

Exactly. Why wasn't the movie written the way I think it should have been written?

Bender is full of shit as revealed by Vernon. School is THE ONLY place where Bender is “important”. So, why would he want to leave that? Andy basically took Bender down without a problem. Sure, he’s got a big mouth and scares people in school but, how far do you think Bender would get in a city like Chicago? I don’t give him a week.

Like most of the "bad kids" at a middle-class school, he's largely a poseur. He wants to act tough and be thought of as a bad boy, and he genuinely dislikes school and his boring middle-class schoolmates and neighbors... but he doesn't actually want to leave school and sink into poverty because he'll never be able to get any well-paid jobs, or join the underworld and spend his life getting shot at or jailed.

Don't get me wrong, I think most high school kids are poseurs of some kind or another - hell, I went to a middle-class suburban school in California, and a bunch of the boys were posing as "rednecks"! They'd wear plaid shirts, jeans, cowboy boots and hats, and they lived in suburbia and none of them had ever been near a cow in person, but they wanted to be thought of as tough manly guys who weren't like the soft suburban kids around them. That's how kids learn who they are, trying out various identities on for size, they get over it and hopefully without dropping out of school in the process.