Fairy etiquette is a strict and exacting art. Different types of fairies observe many different standards of manners, and the ignorant or uninformed risk many dangers when dealing incorrectly with the fairy folk. Brownies and their ilk (the bwca in Wales, the bodach in Scotland, the Manx fynnoderee, sometimes the pixies of Devon and Cornwall, and the hobs and lobs around the British isles) often perform services for families and farmers.
Domestic brownies will clean and scrub floors and dust shelves, while farm brownies will harvest and thresh corn and other crops. Generally they ask little except that their privacy be observed and that a bowl of milk be left out for them every night. The brownies consider this a fair trade, and will become offended if anything else is offered to them. Many be the farmer who, upon seeing the naked brownie working for him, thought to offer it a new suit of clothes. In every case, the brownie immediately left its service.
Sometimes the brownie would put on his new suit and think himself to fine and dandy for work; othertimes they felt the clothes were an insult to their previous station. There is also the tale of a miserly Lincolnshire farmer whose brownie grew accustomed to being left a new linen shirt every new year, but then finally the farmer grew tired of the expense and left a coarse sack out. The brownie sang a quick song before it ran away:
Harden, harden, harden hemp!
I will neither grind nor stamp.
Had you given me linen gear,
I had served you many a year,,,,
Thrift may go, bad luck may stay,
I shall travel far away!
from Brigg’s Encyclopedia of Fairies
Offending a domestic brownie can have far worse repercussions. Many times the brownie will stick around in the cozy house, but will make itself a nuisance intead of an asset. It will curdle milk, drag furniture across the floor at night, bang pots and plates together, and occasionally even assault the residents. It is almost impossible to rid a home of an ill-tempered brownie, and it is very difficult to win again the favor of an offended brownie.
People who saw the fairies were advised not to look closely, because they resented infringements on their privacy. The need to not offend them could lead to problems: one farmer found that fairies threshed his corn, but the threshing continued after all his corn was gone, and he concluded that they were stealing from his neighbors, leaving him the choice between offending them, dangerous in itself, and profiting by the theft.