Nothing obviously out of the realm of possibilty, like "Sakura soloing the Juubi" because that obviously that wouldn't happen.
If Naruto or Sasuke gets the Rinnegan, then I'm just, like, done. It would be so cliche and overused and... Just done.
Naruto...If he gets the Rinnegan Im fine with it...isn't he Rikudou reborn? If so that would make sense at least to me. Sasuke on the other hand there is a possibility, but I feel he doesn't deserve the Rinnegan. I really hope Kishi doesn't do that...If he does I'll be highly reluctant to continue the manga. I might just stop reading from that point on...like with Death Note when they made the second half I believe only to have Light get caught so the "good guys" would win. In my mind Light never got caught, and consider the second half nil. Erased from my memory. I know... call me what you want

but Im human, and certain things do bother me. Or If Hashirama is somehow stronger than Madara, while being weaker than when he was alive, and Madara being 10xs stronger than when they fought. If he beats him by surreptitious means...like a sneak attack thats fine, but in direct confrontation imo Madara should be far stronger in almost every aspect. Given his physiognomy (Madaras) when he sensed Hashirama he seemed to be eager to show off his newly obtained power, at least to me. Which I feel shows he wants to make sport of Hashirama, but idk we all know with Madara and Hashirama...Madara is a glutton for punishment. These two would annoy me the most.
- Sasuke getting Rinnegan
- Edo Hashirama in direct confrontation defeating Edo Madara.
- Any of the Edo Hokages displaying some brobdingnagian jutsu that stops Madara, or the Jūbi. Minus Hashirama.
- If the Hokages easily defeat Madara.
- If Kakashi beats Obito.
- Sasuke doesn't receive amercement.
- If Sasuke and Naruto don't fight.
These are just some that would rub me the wrong way, but its not my manga so only Kishi know what will happen.