Stefan is one of the main characters from The Vampire Diaries who often tries to portray himself as the better brother compared to Damon. However, this is not always the case, especially when his judgment gets clouded by Elena or his bloodlust takes over him.
All this being said, there are numerous quotes that directly demonstrate how much of a villain Stefan can be. They all seem to point to the fact that Stefan thinks he's a better person than he actually is based upon his words and actions.
Stefan On Living Forever With Damon
"Let Them Drive A Stake Through My Heart, Because Then I'm At Least Free Of You."
Stefan spits this melodramatic line at Damon in the first season when the two are at odds about both Katherine and Elena. Stefan, at this point, has fully convinced Elena that he's the morally responsible sibling while Damon is reckless, and this quote shows the extent to which he would go to get rid of his brother.
Even though Damon doesn't fully believe it, Stefan puts real meaning behind these words, which means that he doesn't care about anyone but himself. He doesn't want to repair relationships, he just wants to create new ones where no one can see him as the baddie he really is.
Stefan's Selfish Love
"I Didn't Care I Had Something My Brother Wanted. I Didn't Even Care If I Hurt Him. I Only Knew That I Wanted Her."
Stefan says this when talking about first meeting and falling in love with Katherine. He openly admits to not caring about other people when he's trying to pursue a love interest. Not caring about a stranger is one thing, but extending that feeling to his brother is cold.
Stefan loves to put his love interests on pedestals so that they appear more innocent or pure than they actually are. Because of this, he tries to maintain a perfect yet unsustainable façade that makes him go off the rails in one way or another. He doesn't know how to regulate his emotions and becomes his own worst enemy.
Stefan's Dedication
"I'm Sorry For The Part I Played In Your Death. I Was Protecting Elena. I Will Always Protect Elena."
This quote relates to some of the root problems of Stefan's villainous ways, because it shows that he will do anything and hurt anyone to keep his girlfriend safe. Of course, he loves Elena, but that doesn't give him the right to endanger people in the name of protecting her.
He wants so desperately to be seen as good, but he only really cares if Elena believes he's good. He's willing to kill people and still doesn't see how abnormal that is, especially for someone in a high school relationship.
Stefan On Barely Being In Control
"Okay, I'm Freaking Out. I'm Ready To Eat The Whole Waitstaff. Why Do You Need To Hear Me Say It?"
Stefan yells this after coming off a bender and not fully being able to control himself just yet. He wants to make a change and not hurt people, but the way he specifies the waitstaff shows that tearing people apart is all that he can really think about.
Stefan is anything but levelheaded at this moment, and because he's so volatile he makes it harder for himself to make good decisions rather than impulsive ones. Instead of leaning on his friends for support, he yells this and only makes his hunger and uneasiness worse.
Stefan Verbally Attacks Elena
"Elena, Do You Have Any Idea How Pathetic That Makes You?"
Stefan says this to Elena, which is one of the worst things he does with his humanity off, when she just needs a bit of comforting. He lashes out at her, hurts her feelings, and makes her feel physically unsafe with this line and his demanding tone.
At this moment, Stefan condescends to Elena and makes her genuinely scared. He's always known that he has the mental and physical power over her and he finally uses it to make her uncomfortable and become a villain in her eyes too.
Stefan On Being Unrecognizable After Falling Out Of Love
"You Don't Know What I Look Like When I'm Not In Love With You."
Stefan says this to Elena when she goes to him asking for advice and help after she chose Damon over him. Instead of being the forgiving good guy that he claims to be, he gives her nothing because that's what he's like when he's not in love with her. He doesn't care.
This statement is cruel considering the number of near-death experiences they have been through together, but what makes it most tragic and evil is the fact that Stefan turns her away for no reason other than deriving some kind of joy out of the fact that she's getting a taste of her own medicine.
Stefan While Torturing Katherine
"The Pleasure Of Watching You Suffer Is Greater Than Any Pain I'll Ever Feel."
Katherine, who often survived against the odds, did many terrible things in order to do it. Regarding Stefan, she did a lot of awful things, including compelling him to drink her blood, lying to him, pretending to be Elena, and so much more. But taking pleasure in her suffering is sadistic even for someone who is trying to exact their revenge.
Stefan once loved Katherine, but his lack of forgiveness and ability to revel in her pain makes him a definite villain. She was his first love, but he doesn't treat her like that's true at all. Not even Damon goes so far as to say he likes to see her hurting.
Stefan's Ripper Frenzy
"The More Blood I Get, The More I Want. And If I Get Near Yours, I Won't Be Able To Stop...You'll Be Dead."
Stefan's bloodlust knows no bounds, and while he says he can't control himself, there's definitely a part of him that truly enjoys draining the life from people. He pretends to dislike it, but, at the core of his character, it's clear that he enjoys the feeling of it and the rush.
Saying that he can't control himself is just him openly admitting that he doesn't want to stop. Every other vampire on the show tries to deal with their hunger discretely, but Stefan, who loves giving shady burns in general, also likes the thrill of letting people know he's ready to eat.
Stefan's Blindside
"I'd Turn My Back On Everyone Here To Make Sure Elena's Safe."
This quote of Stefan's shows just how blind he is to reality and how he's not even really in love with Elena. He's driven by the idea of her innocence and his own infatuation with being good.
Being able to turn on everyone he loves for a girl that he's only known for a couple of years is absurd, especially considering Stefan is over 160 years old. It's evil for him to even think about, let alone say aloud for everyone to hear.
Stefan's Uncontrollable Bloodlust
"I'm Not Depressed. I Just Want To Rip Into Someone's Artery And Feed Until I Can't Breath Anymore."
Stefan, who was actually a great boyfriend in some ways, says this after being officially dumped by Elena for his brother. Not only is he going through the grief of dealing with everything that he did with his humanity off, but he's also heartbroken and still hungry.
Stefan's bloodlust is well documented and even though he's in a bad situation, it's still villainous to have the urges and think about killing innocent people when he tries to portray himself as the good guy. He can be a good guy, but he has an addiction that he's not always self-aware about.