Some fey from european (and those from the brittish isle, scottland, and ireland) legends are simply "inscrutable."
Take for instance, brownies. These are often depicted as living inside houses with the residents completely unaware of their shared habitation, where the brownies clean the house when the "owner" isn't looking, and other potentially useful actions. (in addition to several not so useful actions, like eating food, moving furniture, altering the decor, etc.) So much so in fact, that they have incentive to keep a "good, moronic human" in the house they live in to keep their cover. So, if he/she is a baker, they will help with the baking when nobody is looking-- etc, to help that human "keep the house". However, if the human at any time realizes that he/she is a host to these fey, they resent being "expected" to help, and will either switch into full on peevish mode, or simply abandon the home owner to his/her own misfortunes.
The "Evil, make you dance forever", "Turn you into stone", "Turn you into a tree", "Turn you into a spring" type fey are usually the more fickle nature and forest fey that are opposed to human activity. Presumably, they can't reproduce by themselves reliably, and steal human babies to raise up as surrogate children that they then marry off, or otherwise discard later. In place of the child, they leave a twisted magical construct, or failed offspring of fey origin. (Most folklore has this exchanged object being an enchanted lump of stone or clay. In some circumstances, an actual child is present, but it is sickly and unhealthy, and usually dies. The ones that do survive infancy tend to be decidedly non-human in temperament and appearance as they get older.) This is not indicative of all fey however. Gnomes are similar to brownies superficially, and are typically benign. Other nature spirits that could be called fey are considered essential in some european cultures, such as in the ancient norse traditions. The ritual known as the
Nithstang is said to
"Infuriate" these spirits, causing them to vacate the area, resulting in the land becoming barren and infertile, and inhospitable to human occupation. (please ignore the political stuff at the bottom.)
While all of these entities are decidedly "Fey", the "We get off on torturing you with magic, like a child enjoys roasting ants with a magnifying glass" types are only one kind.