I think what makes me happy is several key design choices:
One, the game has a personality/brand/design more interesting than a block of wood. Most games are unbearably generic to make sure as many people can get into it as possible (Candy Crush and all the other Saga games)
Two, the systems feed into themselves quite well, keeps you engaged. In most Pokemon games the collecting aspect loses importance less than halfway through. Here, the collecting is always worth it.
And lastly and most importantly, the microtransactions are not very intrusive. Yes they can help, but the game doesn't brutally pound you into buying them. You just KNOW 99% of companies would have sold star dust or had an RNG candy dispenser.







