Disappointed

Hello Guys, I want to share about my experience this day. In my class I get a high grade in my subject which is a System Programming 87% in my preliminary but I am not satisfied on my grade because in my own thought I am deserving to get a 80% grade. I am not an intelligent guy or bright person but I can understand faster but I'm to lazy to learn more about this subject and I also copying an answer in my classmate and sometimes during in my class I sleep, So I think I deserve to get a low grade, I am not happy because they give me grade that not belong to me but I think if I study hard and focus in my class? I think I can have that grade. I have no time to make opinion about in my life because I have a quiz right now! thank you for listening!
THANK YOU!