Gift Giving Customs in Mordor and Nurn
I think that there would be a lot of customs involving gift giving amongst the human populations of Mordor and Nurn, given the fact that the land was founded by the Lord of Gifts.
Receiving a valuable gift from a person in power would indebt you to them, effectively forging an alliance between you and the gift giver. Because of the imbalance of power, this sort of gift can be both a blessing and a curse. "Gifts are often manacles in disguise, with a chain that is attached to the hand of the giver," is a common expression in the Land of Shadow.
Becoming indebted to the gift giver only applies if they are of higher standing than you, however. If you are the person in power and someone of lower standing gives you a lavish gift, then it is seen as a form of tribute.
Because of these gift giving customs, the citizens of Mordor and Nurn would take careful thought when choosing a gift for a friend's birthday or other special occasion. Even if one is of equal standing to one's friends, there is still a degree of anxiety involved when selecting a gift. Simple gifts are best, so that the receiver will not think that they owe you, but a gift should not be so simple as to be insulting. The right amount of balance would be needed to avoid potential social blunders.
Gifts made by one's own hands - even if the gift is an ordinary loaf of bread - are considered of higher value than goods purchased from a marketplace. This is because it is believed that the maker imbues their creations with both their intentions and the essence of their being. Naturally, the level of indebtedness that one feels for such a gift increases with the complexity of the gift and the time that was involved in its making.
In the more fertile regions of Nurn, flowers might be popular casual gifts to give when visiting friends. Many cultures have flower languages, and Nurn might be no exception, with different plants or plant colors assigned various meanings. Bouquets of nine flowers would be seen as auspicious, due to the association with the Nine Nazgul.
One should never forget the Lord of Gifts either, He Who Is the Lawful Ruler of Middle-earth! It is customary to give frequent sacrifices gifts to the Great One in gratitude for His blessings. One does not wish to anger the Great Eye, after all...
