IMO, everybody has a bit of evil in them. Just some more than others. It's a necessary trait to have under situations of survival. Others are just plain evil and don't know it or can't help it (i.e., George Bush).
So someone calling their grandmother evil doesn't seem that alien to me. I think the issue is when people get brushed with broad strokes -- meaning that there are most certainly good qualities about juvemania_10's grandmother for that matter.
Unless you recognize that there's good and evil in everybody, your view of the world is going to be polarized and you'll be putting a blind eye to anything good an "evil" person does -- or anything evil that a supposed "good" person does.
What else explains why some serial killers are often called nice, gentle people depending on the audience. ("He was such a nice, quiet man...") Human brains tend to not handle the conflicting elements of each individual very well -- it's a lot easier to understand the world in black & white terms where everyone has an (underserved) label.
Watch a flick like "Capturing the Friedmans" and you'll see what I mean.
Buy on AliExpress.com
