U.S. History and Global History (CRR)

I always wonder, why do we need U.S History and Global History class?... I understand that all these wars and horrible people back then has done a lot of damage to this world... but it not like we will need to know this in the future. What matters is now... not the past! Well the past does matter, but what really matters is what's happening now. People should try and start to make a better change in their lives to become a better person. Global History and U.S. History is not really my favorite subject. I don't seem to understand and remember all the things that happened in the past. There is a lot of things that happened in the past that we need to remember, but it's just so many. For some reason these classes and I don't seem to connect. I try my best to listen and understand, but it seems like it just goes through one ear and out through the other ear. Others find this subject pretty easy and that's great! I hope I do well on all my regents ...especially U.S. History regents!