
While most of pve is "fixed", there are some variable things that happen and learning how to deal with those that can be fun.
I would propose the same question to you, why pvp all the time? After going up against the same person again and again, doesn't it get old? They probably tend to run the same build and bring skills that are easy to predict.

Apollo, this isn't a flame, but you're probably in that guild for a reason. =P lol