The entire opera scene for a start. I mean, really, now. Not to mention Kefka actually somehow rising up through the military ranks without anyone realising he's pure evil. Sabin suplexes a moving train. Do I really have to go on? xD Every FF is full of things that are unbelievable.
If you're legitimately saying that FFVIII is worse than all the insanely terrible or outright broken games that have ever been made, well... yeah.