speaking of grades here, my world cultures teacher makes sure we have the easiest tests to take, im not sure whats wrong with him...but a 3 year old could pass these tests and get a 100% on it without even trying.
my science teacher on the other hand...my gawd lay off with the college material lady!!! 
My Chemistry teacher was a Dr. and I learned more from him than anyone else. Kids always complained that he was teaching college level stuff but that wasn't true. He taught it like it was a college class but the material was straight from the state curriculum, he treated us like we were adults, and expected us to learn the material one way or the other. Seeing him after school or during lunch was fine, and I took up that opportunity several times. The way he taught the class and designed the tests meant if you didn't take the class seriously, you failed. Kids always had excuses like learning disorders and lack of time, but I did most of my studying in school while everyone else was gossiping and playing with their phones and I figured out a way to know the information that worked for me.
I learned a lot more than Chemistry in that class, it was my favorite class in HS because it was actually a challenge and I only got rewards for actually working. Shocker.