Teaching....Misery/Happiness...

I am a 15 year old teenager and i have a job. Thats normal, i teach students of grade 8 that's because i am in secondary 2 meaning grade 11 well i skipped a class, because i am kind of smart.
SO i have two students , both in grade 8 teaching them is tiresome but it gives me pleasure when i realize that they got grades and that they are becoming better. So i have a student , mario, he is supposede to get good grades, average. Well i know his abilities so if he doesnt get good grades i'll get so upset, but then i 'll be happy again becuase he'll do better the next timme. Where as my other student , Yeves he is so tiresome, and his average was not that good but when i started teaching him his average started raising and i liked that. Today i am overwhelemed because he got a 76% on his math test and that is like amazing.
So from mario i expect good grades and a smile but from yeves i simply expect him not to fail, so whenever yeves gets a good grade i'll be filled with extacy. Ok thats all, hope you get the idea of Misery/Happiness....