Harry Potter: Ranking Every Hogwarts Teacher From Worst To Best

Unlike the previous Potions teacher, Professor Slughorn is jovial, kind, and enthusiastic. And despite his initial reluctance to come out of retirement, he enjoys teaching Harry and his classmates.

Slughorn also has a society at Hogwarts known as the Slug Club. The group consists of talented students who Slughorn believes will go on to become outstanding witches and wizards. Sure, the group is a little elitist, but it’s still an interesting part of The Half-Blood Prince – no other teacher has their own society.

Most importantly, however, Slughorn gives Harry a memory relating to Voldemort’s past. This memory tells Harry and Dumbledore that Voldemort made six Horcruxes (not including Harry). It's a vital piece of information, therefore, for Harry’s quest in The Deathly Hallows.

All things considered, it’s a shame Slughorn doesn’t appear until The Half-Blood Prince. He has a distinctive personality and his lessons are always fun.