Feeling obligated to return a favor, share resources, trade an item, etc.
"You can donate or receive materials everyday, from your guild members or friends outside of your guild. The game encourages this donate x donate system."
"Allows you to create and share maps with other players. Basically a mod system. Please inform me if this does not fit the criteria."
"Trading resources was a popular feature of this game. Due to the nature of season pass tasks, you were frequently required to wear or swap certain hard-to-obtain items, which would sometimes require you to lend or borrow from complete strangers."