Whoever put voted Snape, I hope that you realise your mistake.
Snape wasn’t the best teacher, and was definitely hard on his classes, especially on the Griffindors, but he definitely taught them what they had to know, and in the end he may as well have been the single most determined character in the whole story, spending literally years not giving a single person a hint of who’s side he was really on.
This has nothing really to do with teaching particularly, I’m just saying: don’t diss Professor Severus Snape.