I used to be an average student who didn't take his studies too seriously. When I went to high school, things changed. I shifted my perseptive and started to take my classes and my studies seriously.
If I hadn't studied hard and gotten good grades in High School, I would not be where I am today. I once had a teacher who used to say, "Study hard, learn lots."
Education is valuable. It will take you places you never thought you could go. In general, you never know where hard work and persistence/perseverance will take you. But that's the beauty of it. Value education. Value learning. Value growing.
In addition, whether or not you like the subjects you're studying (I'm speaking primarily to college students), you can still learn from them regardless, as you learn from everything else in life.
(initially written 10/05/2011)