ungrateful parents

So i got my report card and i did very well but my mom is still not proud of what i got.My average was a 86 and my mom said shes not satsified, i know i can do better but still i did very good. Sometimes parents are so ungrateful and they dont understand that we are doing the best we can and we are not perferfect. When i get older and have my children i am not going to be as hard on them as my parents are on me. I will understand them and be proud of them for trying to do good.