KH1: Riku-Ansem battle. Still haven't beaten that and it's been years. Wonderland too, I hate it.
KH2: The difficulty compared to KH1. It took me two days to beat the first world of KH1 but then 2 days to beat KH2 lolwut?
I've had several moments like this. Just recently,I had a mental breakdown about things like this. I can't fight worth a damn(or can I, I've never been in a fight in my life), so I simply ignored them. Of course, It got to me after about a year or two of the same thing over and over again -_-. My parents noticed a huge drop in my grades and my inability to hold a long conversation(I still can't now), and they went straight to the principal after I told them my story(they thought I was following -_-), after that, I have no idea what happened between my classmates and the principal, but they just stopped. I'm fine with my grades now, but I'm still quiet and my self esteem is probably permanetly screwed, and I can't barely make a friend, but the ones I have are REAL friends. But I know know now that if I would have told someone, none of this would have happened.