What is the point of final exams?

I was just reading the requirements for my kids' final exams, which are twenty percent of their grade and have to last at least two hours. I also have my own final I have to take before Wednesday, which is meant to take two hours and is half of my grade for the year.

I don't really understand the point of these things. If we've been doing well all semester why do we have to regurgitate it all back up again at the end of the year? What about those of us who do poorly on tests? I do particularly poorly because the conditions of the exam trigger PTC - fluorescent lights make me throw up and give me a headache, in fact the first exam I took for this class made me so sick I was useless for two or three days afterwards, taking lots of painkillers and whining a lot. Then there's the fact that they won't let me lay on the floor to take it...

What about kids with test anxiety who have managed to muddle through the rest of the tests in the class and now face the risk of blowing the entire semester on one test. Or what if you're sick? I'm taking this whole math class over again because I missed the final exam the first time because it was the day after Dan died and I took the makeup exam the same month I spent 21 days in the hospital with a retroperitoneal bleed and a giant blood clot. That's certainly going to prepare you for a final worth half your grade. I got a 52 on it and am somewhat surprised I did that well.

I can see one more test at the end of the semester on the new material, but this going back and having to do everything over again and making it worth so much of your grade makes no sense to me.

Is it a throwback to some other teaching system? What possible use is it? I don't see anything positive from this at all.

Oh yeah, what about people who stay up and cram and then forget everything? That's good for your body and your memory. Not.