Board Thread:Episode Discussions/@comment-1181222-20170816102343/@comment-32874078-20170816174737

Crazylazyguy wrote: Sharingan is unlocked when an Uchiha suffers an emotional trauma, not when they "need" it. I didn't mean Sasuke unlocked it because he needed it, I mean he unlocked it at the perfect moment BECAUSE he needed it.

And it isn't always an emotional trauma, I don't think you could call Obito seeing Kakashi getting stabbed in the eye and having an opponent with an invisibility jutsu an "Emotional trauma".