Share what you have learned in class with classmates who can't catch up with the teachers. In the process you will learn more than you have been taught. And, before you call anyone "stupid", find out if there is a learning disability and discover other ways to teach.
Survival of the fittest is a rule of nature and part of the food chain process. If it's a need, don't waste it. Think of the animals killed to feed you. Don't throw away your food.