Favor represents your current relationship-status with a certain NPC. Favor is raised by giving specific gifts to NPC's, according to their likes and dislikes, and completing quests.
By raising your favor with that person you'll receive various rewards such as:
- increased value on items sold
- ability to utilize new skills
- experience
- special recipes
- ability to list a limited amount of items for sale to other players (aka "consigned items"), which is similar to auction houses in other MMO's
- and most importantly
Even when you are not interested in what a particular NPC has to offer, you may want to be able to sell your loot to them. Earning Favor with NPCs that buy your items will give you much better price as your relationship with them improves, up to the point where they buy items at full price.
Until you reach high favor with a merchant NPC, you will see a little exclamation mark icon (!) that informs you that they are not buying your items at their full value.
Generally you'll want to gain high favor with most NPCs, however it is worth noting that some NPCs will buy a great variety of items, or buy items that sell for a good price (such as weapons and armor). The location nearby to a dungeon or a teleportation circles can also make certain NPC merchants much more useful.
Relationship levels
By reaching 100% favor you'll take the relationship to the next stage. Each tier of relationship has diminishing returns. The different stages of relationship you can achieve with an NPC goes as follows:
| Relationship Status |
|---|
| Tolerated <- Neutral (Starting) -> Comfortable -> Friends -> Close Friends -> Best Friends -> Like Family -> Soulmate |