Relationships
Relationship-building is a core gameplay mechanic in Echoes of the Plum Grove. The Player has a relationship status with every Villager on the island, including their family members, but not including Sailors or Tourists from the ships. Strengthening relationships with NPCs leads them to give you spontaneous gifts, and is necessary for a successful proposal and marriage, and therefore to advance generations. Relationships can be improved by talking, gifting, or completing quests for villagers. Insulting villagers will damage the relationship with them (although it may be necessary for other villagers' quests and relationship advancement!)
The Village tab shows the status bar for the player's relationship with each individual villager (including villagers not met yet). It may be neutral (all white = 0), positive (green/on the right = 100 when full), or negative (red/on the left = -100 when full).
Building Relationships
Talking
You may chat with any NPC on the island by selecting the Talk dialogue option. This can be done twice per day. Their dialogue will reveal their preferences and hobbies, information about the island, and their opinions on other NPCs. It will also raise the relationship status bar. Some NPCs profess to not like chatting, but they will still talk to you.
It is possible to repeatedly talk to Visitors and Ghosts, even though there is no relationship-building mechanic for these NPCs.
Gifting
You can gift items to NPCs once every 3 days by selecting the Gift dialogue option. NPCs have particular preferences and tastes, which may be revealed through dialogue. A gift can be appreciated or disliked: dialogue will me more or less polite depending on NPC traits, but the post-gift facial expression shows how it was received. Smiles indicate the gift improved your relationship; flat affect and squinted eyes means it was not successful. Some items are universally beloved gifts: expensive ores and jewels, expensive crafted items, meals, and roses are broadly popular.
Questing
Villagers will propose quests to the player, either at the town notice board, by mail, or in conversation when they have a question mark over their head. Completing a quest within the time limit will yield the specified quest rewards and also relationship improvement with the NPC. Though some characters have whiny, impatient, or ungrateful dialogue, you can still build relationships by doing their quests.
You may be offered quests that are impossible to complete, asking for out of season items or crafted items you don't have the blueprint for.
There is no penalty for failing or rejecting a quest.
Damaging Relationships
Insulting
You can insult any NPC on the island by selecting the Insult dialogue option. This saddens them and decreases the relationship bar. Villagers with the "Mean" trait will respond positively to the player insulting other Villagers and may even give a quest to insult villagers.