When we read Beowulf in high school, one girl in class tried to argue that Grendel was a sympathetic character. Here is a contemporary paraphrase of my 17 year old thoughts:
"You P.C. thug. Grendel is evil because by all conventions he is evil. This poem was written long ago and you can't apply your modern day sense of morality and injustice to what is quite obviously the villain."
A few funny things happened on the way to adulthood, of course. Funny things like college and grad school.
And Anakin Skywalker of Star Wars Episodes II and III, and Elphaba of Wicked, the novel and musical, and Judas Iscariot of Jesus Christ Superstar.