Kakashi asks Sakura about a math equation now confirmed to happen in the future.

I think SOME characters are difficult to use well but not nearly all of them. The OC's and canons debacle can be cool, but not when it's meant to be played out as a character getting smitten by an OC instantly when they've never been huge on the opposite sex anyway. Like, imagine Shikamaru of all people being forced to be smitten by some new chick who is magically smarter than him or something stupid like that. I used Kakashi with some girl's OC once and she made Tsunade kiss her character's ass so hard it was pathetic and discomforting. I am ALL for OC's but not when you just want them for a power trip or to make yourself better than everyone else. She even had Tsunade threaten Kakashi if he messed with the OC, how lame is that shit? But OC's can be great, I just think you're not used to having good ones :D