You put so many hours into a game in order to get your protagonists ready for the end battle to save the world only to find out that your party cannot die and the boss can be beaten with a few hits.
Now if you follow the story of Final Fantasy X, it does make sense that Yu Yevon is such an easy boss to beat. He is a parasite and cannot survive without a host. Even so, the last boss of any game shouldn’t go down after one or two turns. Plus the fact that your party cannot die takes a bit of the fun out of a final battle. Granted, leading up to the final battle, your team must fight all of the summons (known as Aeons) as well as Jecht, which can be a bit challenging for some people.
I love this game but when I first got to this boss, I was a bit let down at how simple it was to beat him. Compare him to other final bosses in video games; Yu Yevon is pretty much the worst.