"Why wouldn't you travel by main roads?"

Episode 2, Four Marks - Yennefer

This is very much Yennefer's episode - she gives it its title, she gets the opening scene, and the other stories, with elves and prejudice, tie into her own.

Yennefer's part starts well before any of the other events we've seen. According to the timeline, Renfri's story is a quarter century after this and Jaskier meets up with Geralt a decade after that. Yennefer is fourteen.

We open with a couple, neither of whom seem particularly pleasant people. Despite that, Yennefer picks up the flower the girl throws away and tries to hand it back to the girl when she looks for it.

This does not go well for Yennefer.

Girl: "Ugh! Now it smells of pig shit."
Boy: "You been spying on us, you creep?"
Girl: "'Course. Look at her. No one's ever kissed that."
Boy: "Could she even stand up straight to do it?"
Girl: "Where you going, crooked girl? We can teach you."

In the first episode, Geralt told Roach the story of how he learned kindness gets rewarded with rejection. The lesson Yennefer learns about kindness is even worse, that you're rewarded with assault.

Of the main characters, Yennefer is the only one we know (explicitly see, in fact) this happens to. They each grab her. She struggles and can't get free. They shove her to the ground and hold her there, pawing at her. They first insult her that she's unwanted, but immediately move to threatening to sexually assault her. She reacts extremely badly when in a few minutes Istredd says, meaning magically, "Oh, you're a virgin." We don't know how far they would've gone. And neither does Yennefer.

I'm assuming that fandom is primarily just being oblivious here, but it is really, really fucked up that it's someone we see narrowly escaping that fate who is people's go-to for rapist and rape apologist. This is, in fact, the worst it gets for the entire show - rape is brought up several times but never shown on screen. And it's not buried in her character arc, it's her introduction and it's why everything else happens: she's so terrified by what's happening she taps into magic in order to escape.

Yennefer: "Leave me alone. Stop."
"I heard your father makes you sleep with pigs."
Yennefer: "Stop."
"Your own family doesn't even want you."

She has to use magic because no other option is available to her. She is not strong enough to make them stop (and if she could fight back and harmed them, she'd be the one in trouble). And they don't care that they're told to stop. They're not doing this because they don't realize they're hurting her, they're doing it to hurt her. They know they can do it without consequence because no one else will care either. It's not just them, either, anyone around her can hurt her, probably wants to, and will be allowed to by the rest of her community. And this is because she is ugly/crippled/unloved - all things outside of Yennefer's control.

(We'll see in a moment that saying her "family" hates her isn't quite accurate, but the real situation is just horrible in a different way.)

So she uses a portal to escape. Not to hurt them back or even stop them, just to get so far away they can't hurt her.

(This is, I think, an example of how she and Geralt are alike yet struggle to hold a relationship. Two people with abandonment issues who respond to stress by running away.)

Istredd: "Who are you?"
Yennefer: "Wha- what is all this? Am I dead? How did I get here?"
Istredd: "Well, it looks to me like you portalled in."
Yennefer: "I what?"
Istredd: "You know, portalled. From wherever you were to here. The Tower of the Gull. Aretuza. Oh, you're a virgin."

Yennefer retreated, struggled, begged and finally ripped a hole in reality to escape this, and all it's accomplished is now her back is against an unfamiliar wall. Terrified, she hits him, only to panic further.