... I'm the first one to say "the plot," aren't I? I like making up personalities for my trainer, and play through the game imagining that personality.
They're ridiculously corny, but fun. I'll start a new game in Emerald and say "Okay, this boy's secretly joined Team Rocket without letting his parents know and he wants to defeat Teams Magma and Aqua to clear the way for a Rocket takeover of Hoenn," or I'll start a game in Pearl and say "This girl doesn't actually care about gyms, she just wants to collect rare Pokémon and so she beats gyms to get the HMs to reach them, and the only reason she beat Team Galactic was to take Mesprit, Uxie, and Azelf for herself."
And I can play through the exact same plot over and over, but as long as I keep imagining different characters (on a previous Pokémon Emerald file, I was pretending to be an extra-terrestrial with self-esteem issues...) it stays new.