My worst moment was when I was about to beat Sephiroth on Expert mode in KH II and I used Curaga, went into MP Charge, and I had Beserk Charge on so I couldn't use finishing moves! So I couldn't kill sephiroth until my magic returned! I lost too!
Another time was when I was about to beat Sephiroth I (after another try. He had 1 HP) I was about to do the finishing move when my wireless controller died! I tried to plug in my other controller but he killed me! I lost again!