Yeah i've done somthing like this before i can't remember half of them now though but here's afew.

1) in a fight you are convinced that you have different classes and change from theif to mascot (no i haven't done this but it's quite good and amusing when i see other people do it)

2) Your in a fight and tell your opponent to use the flee command cause you have a limit break ready.

3) you try to go on an adventure like cloud without ever going to the toilet eating taking a bath and are surprised when your bladder bursts.

4) You try to have a game of blitzball and are surprised when you drown.

5) You are convined that penguins in alaska know the fabled blizaga skill and decide to go there on a quest to learn it for yourself.

(i still have afew more but i'll let afew more people post)