You know, it's always about the family drama for me. The biggest conflict isn't even necessarily Sasuke and Naruko themselves, but the Uchiha and Senju baggage they're born into. Every writer has to navigate the whole 'destroyer of my clan' versus 'daughter of the village' thing, and they either lean super hard into the Romeo and Juliet of it all, or they just handwave it away which feels cheap.
I get bored when the conflict is just 'Sasuke is emo and Naruko is too loud'—that's surface level. The more interesting fics pit their core philosophies against each other. He's about destiny, revenge, and a narrow, intense focus. She's about breaking destiny, forgiveness, and connecting with everyone. That clash can lead to amazing arguments where they're both right and both wrong. It's not about who wins the fight, but whether their worldviews can coexist.
I've seen a few stories where the conflict is purely logistical, which is a fun twist. Like, he's a missing-nin and she's the Hokage; how do they even meet without starting a war? That forces way more creativity than another rehash of the Valley of the End. My personal favorite is when the author uses Sakura or Kakashi as a third point in the tension, not necessarily as a romantic rival, but as someone who represents a path or a loyalty that pulls one of them away.
The worst ones, honestly, are where they make Naruko a doormat who forgives everything instantly, or Sasuke a soft boy with no edge. The conflict should leave scars, you know? It should change them. Otherwise, why am I reading about these two specifically? Let them fight!