In the game you have to save the cat from getting hit by the ball.
The cats behavior is expressed when it gets hit by the ball [surprised] or makes it way from it [happy].
We have some more "Pokemon Go" news for you because we are certain there is no way you are tired of hearing about this yet. Let's get to it before you throw yourself off your seat in excitement.
If the possibility of discovering a dead body, or getting IRL robbed at a Pokestop doesn't entice you to play this game, perhaps its matchmaking qualities will.
If you're willing to fall in a ditch or piss off your already-crotchety neighbor by trespassing on their house-turned-accidental-Pokemon gym, you'll probably have no problem catching a date with that Jigglypuff.