Now, everyone seems to think that they're such benign little things with gossamer wings and voices like the wee-est bells...
Maybe that's so. I can't speak for all of them, or even most. But I'd treat them with some respect and maybe even a little distance, if I were people today.
Now, the faeries don't like to be spied on by humans, kids or adults neither, and they go out of their way to make sure no one sees them. They hide themselves in hidey-holes underground, or in cellars and basements, back in the farthest reaches so people don't find them. Some of them like to be near people. Curious, I guess. But don't get too curious about them, or they'll make sure you know better next time!
They don't like their hidey-holes found out, either. If you find one of them what lives alone, he'll up and leave. Never a word, he'll just up and leave and take his magic with him. Because they do bring magic to places they feel safe in being. Some of them help keep the house clean, once they figure out you like to keep it clean yourself. Or they help out with the business, like in the story about the Elves and the Shoemaker. Once they were discovered, though, they took a powder like they'd been caught in someone's sights, never to be seen in those parts again.
They don't like laziness or slobbery, and they don't like people pestering them. If they're found out by humans, they give a false name so you can't capture their glamour. A name's a special thing, contains the essence of a person and breaks their spells. That's why the queen in the story of Rumplestiltskin had to find out the little man's name or else lose her child - not knowing his name kept his magick intact. Finding out a faerie's name could make them give up their worldly treasures, too. So they're extra-careful about their names.
Now I don't know about this New Age prattle about beneficial faeries wandering around performing good deeds and being favourable towards humans. Seems to be so about a few of them, where they think it's deserved. But they do like to capture humans and keep them in their faerie realms.
Funny thing about those faerie realms. A year is a minute and a night's twenty years. If you remember the story of Rip Van Winkle, you know how they can fool you into thinking they're normal sorts of folk who mean you no harm and are just out to be neighbourly. Then they get a spell or potion down you and you wake up twenty years later, the world has changed, your children are grown, friends dead, and there you are without an identity or family to call your own.
Anyway, they do take people down into their underground caverns and keep them there for years. There have been plenty of tales told about people disappearing and coming back not aged a day two decades later. They tell tales of wild parties and strong drink, then of remembering nothing until waking up years later.
They also take children, especially infants. Now, some say that people only say this because it explains sudden illnesses. These people will say that their child was exchanged by a faerie mother for her own ailing child. Or, a normal, bright child will suddenly grow distant, be 'seeing the faerie realms' and the parents will explain it this way. Now, this might or might not be so. Modern medicine has labels for children like this. But they do see farther into the Other Realm, I've seen them laughing at the goings-on down there.
And they can fool you. They seem so ordinary! They look just like people you'd meet on the road. And they lure you in with kindness, promises of a place to stay the night or supper.
But there's something strange about them. They know your name without you having told them. And, they'll never give you theirs. They just call out to you and remark on how late it's getting and how dark and treacherous is the road, and that's all it takes for you to fall into their clutches.
They troop around at various times of year. Winter Solstice is one time where it's safer to stay indoors and out of harm's way. Beltain, the eve of the first of May, is another. Stories are told of how they trap unsuspecting humans hurrying home at these times. Funny thing is that these same people who were taken un unawares like that were trying to get home before the faeries were abroad!
Faeries live underground, or in the woods or by healing springs. They're the guardians of the land, having been here before us and all. And they take a proprietary view of everything on it. Their homes are entered through sacred mounds, as they're called now. You walk three times around by the sun and you can find the entrance to their realm. But be careful if you do, remember what I said about how they like to capture humans!
There are ways to protect yourself from malevolent faeries if you need to. Turn your clothes, inside-out is fine, or backwards. Makes you look topsy-turvey to them, like you're heading in the other direction. They also don't like water much, least running water like a stream or a river. Cross it where there's no bridge and they'll be left standing on the far bank from you. Or cross iron. Faeries don't like iron much, sets their bones at odds. So crossing iron's a good idea.
You can keep them out of your house by use of charms and spells and talismans. One good talisman is a witch's bottle. Fill a bottle with little things, like fennel seeds or tiny beads, and hang it by your door. The faeries like little things and will be stuck there counting all the pretties in the bottle until sundown, when they have to go back to their realm. Or keep a witch's ball buried somewhere on the property. Fill it with twisting, knotted things and the faeries will have to follow all the twists and turns, maybe even get themselves stuck if you put bent pins in it, before they can come any farther. But they always have to return to their realm at dark.
I guess that's why it's not as safe to travel at dusk through the Faerie Woods, or down along the river after the sun has set. They have to get back home and are desperate to get a victim, those who do that sort of thing.
Of course, you could make peace with them. Live with their conditions. Don't try to find them out, respect their privacy, give them little gifts the same as you would a human friend, and just basically get along. I do that myself, since they've been living down in the old coal cellar of our basement for more years than I've been alive. But I don't tempt them, and if I do go down, I wear myself a knotwork of some sort to keep myself safe.