Appendix:Happiness

Happiness, also known as Friendship, is a hidden value in Pokémon that reflects how much kindness players have shown to their Pokémon, and in return, how much those Pokémon believe in their trainers. It is critical for triggering the evolution of many Pokémon species, encouraging trainers to bond with their Pokémon. Happiness also controls the power of 2 certain attacks.

About
First applying to the player's Starter Pokémon Pikachu in Pokémon Yellow, Happiness was quickly expanded to all Pokémon and has become an important aspect in almost all core series Pokémon games, as well as the Pokémon Anime to a certain extent. It is expressed in a hidden value between 0 to 255 for each Pokémon in the player's possession. A higher value means that the player has a close bond with his or her Pokémon, while a Pokémon with a lower value has a weaker relation with its trainer. Note that each Pokémon has different values, with Buneary and Type: Null starting with no happiness at all along with many Legendary and Mythical Pokémon.

Activities
There are many different ways to increase the Happiness of a Pokémon, including walking or running for some time with the Pokémon the player wants to raise Happiness in the player's party, levelling up, using certain items on Pokémon, as well as winning important matches, such as Gym Battles or Pokémon League matches against the Elite Four and the Champion. On the other hand, fainting and usage of herbs will cause the Pokémon's Happiness to plummet, while trading resets the Pokémon's Happiness to the base value, unless it is traded back to its Original Trainer, where according to a change in effect from Pokémon X and Y onwards and carried to Pokémon Brick Bronze, its Happiness will be restored to the value before being traded.

Items
Some items affect the amount of Happiness a Pokémon gains from an activity. They are the Soothe Bell, Luxury Balls and Friend Balls. Soothe Bell is a held item that doubles the Happiness value gained. It is given by Main Developer Kevin Cat in the Skitty Lodge on Route 16. On the other hand, Luxury Balls are a variation of Poké Balls that have the same effect of Soothe Bell for the Pokémon caught in these balls. They are sold in Poké Ball Emporium, Anthian City - Shopping District. Friend Balls are another kind of Poké Balls that automatically set the base Happiness value of Pokémon caught in these balls to 200, making them significantly closer to evolution, but they are not available in Pokémon Brick Bronze currently.

Happiness-based Evolutions
Here is a list of all known Pokémon evolving by gaining sufficient Happiness. Friendship-based evolutions occur after a level up when a Pokémon's Happiness value is at 220 or higher. Blackened rows mean that the Pokémon are not obtainable for now. Note that some Pokémon can only evolve in a specific time of a day.

Happiness-based Attacks
There are 2 attacks with variable powers according to the Pokémon's Happiness. Return's power is in direct proportion to the Happiness value, reaching the greatest power with Happiness at 255. Frustration works in the reverse, being in an inverse proportion and being the most powerful when the Happiness is 0. Both are purchasable TMs in Colosseum Marketplace, while Buneary learns Frustration naturally at Lv. 13. On the other hand, its evolved form Lopunny learns Return at the same level.

Happiness Checker
The Happiness Checker is inside a normal small house located in Brimber City. He evaluates the Happiness between the player and his or her leading Pokémon. The following table contains all quotes from the man and the corresponding range of Happiness value to the quotes.

Trivia

 * Buneary is widely known as one of the two hardest-to-evolve Pokémon that requires Happiness to trigger evolution, as it has once been the only non-Legendary and non-Mythical Pokémon to have a base Happiness of 0.
 * Type: Null now shares this trait after being introduced in Pokémon Sun and Moon.
 * Most Baby Pokémon require a Happiness value of 220 or higher to evolve.