Let's put it into prespective:
School is VERY loving important. Even if you think that some parts of school are pointless (and some are) That does not mean you should blow off the entire thing. If you want to go rot in a loving fast food restaurant, be my guest. Just have fun living in a stuffhole of an apartment in a bad part of town.
Furthermore, working at a fast food restaurant is even more like a prison than ANY school system. Yes, you can leave any time you want, but then you don't get paid and lose your stuffhole of an apartment you call home. You will have bills to pay, and taxes are an amazing pain in the ass. Without anything at or above a High school education you will never have nice things because all you will be spending it on working in fast food are bills, food, gas, and taxes. Want a nice new TV like you had in your old house with your parents? Too bad, spent all your money on gas last week because you can't get to work because you didn't get a decent education. Stay the forget in school, and then mabye you can get a decent non-dead end job that will take you somewhere in life.