If it actually has impact, like the Nugget Bridge question would have had, or just declining the Pokedex, or even something stupid like if my Rival asked me to battle. I just want to say no before the post-game comes and takes my interest away... I promise to come back and say "Yes" because whatever it is would most likely be useful, but I'm tired.
TIRED of the professors laughing at me, TIRED of my friend/rival treating my answer like it was sarcasm, TIRED of people not listening to me, TIRED, AND I WONT STAND FOR THIS!
EDIT: I know Gamefreak is in control, but I generalize. --- Quoting the Topic Creator's original post is stupid and redundant. I'm here for intelligent arguments or flaming. It's your job to decipher which.
By all means, If you don't want us to mess up the storyline, then make it go as in the Mystery Dungeons, nothing changes. (e.g. If you say no, Professor Oak will keep pestering you or something) --- I loathe Gen V. I am being optimistic for Gen VI, because I hope they can make a good new feature.