Why do I go to school?

Sometimes I don't see the point of going to school. I usualy end up arriving at school, looking at the white board situated in the foyer and noticing that I have a spare. Somedays I end up having two spares. I feel like I waste half my time sitting at school rather then being in class learning. Teachers should tell us in advance if they are not going to be there, because we are humans too and be have the right to know when we have class and when we don't. Imagine if a teacher came to school and got sent home because their students never showed up and they had no one to teach. I come to school everyday, prepared for a test, or a project presentation and then they end up being absent. I understand that, YES, people do get sick, it happens. But I have teachers that know that they are going to be absent and are too stuburn to tell us. I swear they do it just to make us mad. It's frustrating to come to school at 8:30, and be done at 11:00 and have to wait for the bus for 4 hours. It's happen to me numerous times. Anyways, as a student I usualy take advantages of my spares and work on homework. But there are somedays that I have completed all my homework and I have nothing to do at all. Anyways, I'm not saying all teachers are like this or anything. It's just a huge piss off!