"The more you play with your Pokémon, the friendlier they will become. As your Pokémon becomes more friendly, it may perform better in battle—by avoiding opponents’ attacks, landing critical hits, and more!"
http://www.pokemonxy.com/en-us/whats_new/pokemon_amie/GameFreak is basically telling Smogonfags to fuck off finally. Discuss how people will just hack the value for this to max and nothing will change except for Karenfags and Pokephiles swarming all over this feature.