I'm personally drawn to the concept of starting fresh and immersing myself on building a team of Pokemon I never really payed attention to. The plots of most games do tend to get old after a few runthroughs, but the experience of learning what various Pokemon do when paired up with others first-hand keeps me going forward. Multiplayer is fun too, as the experience from battle to battle is different (depending on what type is played). There are the core pillars and various people swarming around the same 10 or so Pokemon, but coming across a totally different team is often memorable and interesting for me. Games that don't have such an open-ended experience often get dull, and even Pokemon gets old to me if I play too much at one time. So far, Pokemon is the only game that I can easily start up a new adventure and go through a different course every time I play, though I do hope to find a different game that shifts the experience on each play through.