I've been thinking a lot about villains. Fiction provides us with a range of examples, from Hansel and Gretel's witch in the woods to the flat yet grandiose evildoers in Marvel and DC Comics movies. As a general rule, super villains don't appeal to me. Storytellers insist they represent an intrinsic moral decay in society and/or the corrupting influence of power. But these characters are often two-dimensional. In the world we live in, there are many villains that share reality with us. Just turn on the news.
It doesn't take extreme loss or sorrow to make a villain. This is a misconception nurtured by those who believe humans are inherently good. To become a villain, a person simply needs a lack of compassion for the victim along with means, motive, and opportunity. The motive can be self-preservation, a need for a resource, or simply the desire to see a particular person suffer.
Lately the concept of the well-groomed sociopath has taken hold of public imagination, but only 1 out of 100 people in the US population have psychopathy. The vast majority of people who do terrible things are not mentally ill. They're just assholes.
Your horrible teacher from childhood who made you cry, that man who shoved you out of the way when you were on crutches, the bus driver who threatened to run you over in the crosswalk, the nurse who dismissed your suffering, these people were your villains. In your life, you will encounter people who take pleasure in the misery of others. They put themselves into positions of power to make you, or someone like you, unhappy. Some want you to fail at the things you cherish. If they can't make you fail, they try to tarnish the things you love with ridicule, sarcasm, and resentment.