In the 21st century, the popular social networking site Facebook has made a verb of the term 'friend', and it is now common to 'friend' people on Facebook / field numerous 'friend' requests on a regular basis. However, it is not always clear what the purpose of being Facebook 'friends' with someone actually is.
In the case of an individual who is geographically distributed from you despite the fact you work together, or the individual once lived near you or attended school with you, it makes logical sense to be Facebook 'friends' so you can see the pictures and updates from their life where you are not present [assuming you genuinely like this person and are interested in remaining connected to them in a superficial regard].
In the case of individuals with whom you are locally socially acquainted and enjoy hanging out, it makes logical sense to be Facebook 'friends' so that you can invite your friends to events, view which events people plan to attend or receive invites to friends' performances or parties; in other words, Facebook acts as a connective device that is easier than calling/texting everyone every night to say 'what are you doing, let's do something together.'
But we currently abide a culture where 'friend' doesn't really mean 'friend' anymore, but 'someone I clicked on via the internet', 'someone who has for some reason given me permission to be a spooky voyeur' or 'someone into whom I placed a digital hook in the event I might want to use them for something someday.'
In an effort to reclaim some semblance of meaning for the word 'friend', consider undertaking a Facebook 'purge', whereby you 'unfriend' everyone who isn't actually your friend nor someone with whom you are interested in being friends or getting to know under consideration of being friends.
One time you were hanging out with some friends and they brought a couple people you had never met, and after attending a social event such as a band show, bar night or raucous dinner you all went to someone's house/apartment, possibly your own, where everyone sat around drinking while listening to music or watching a movie and talking over it.
'The Rando' was the person who sat at the very end of the couch and didn't say very much, possibly even drifted off with his mouth open while sitting next to someone you knew. The next day 'The Rando' sent you a friend request and you said to yourself 'I hung out with that guy, I guess we are friends now' and accepted it.
You never see that guy again. One day he pops up in your feed and you asksomeone 'who was that rando guy', and nobody in your social circle reports actually being his friend, maybe someone goes 'oh, that's just this guy I know.' You should delete him from your Facebook friends.
You received a friend request from someone you have never met, but who has a high number of friends in common with you, possibly a list of mutuals who are closely associated with one another such as your colleagues or a certain 'subset' of your social circle, and you said, 'oh, this is a friend of theirs', and you accepted the request.
However, you have never met nor corresponded with this person. Looking at your friends list one day you see an unfamiliar name and go 'wait, who is this again?' and you visit their profile and notice they do not live in the same state as you or your 'mutuals', they have a career in a field wholly unrelated to yours, and possibly they have a very high number of Facebook friends, meaning that the 'mutuals' were possibly coincidental. You ask your 'mutuals' who the person is and each tells you they just accepted the 'friend' request under the assumption that the individual was a friend of the other. You should delete this person from your Facebook friends.
The 'Networking Opportunity'
You received a friend request from an individual in a career field related to yours or in a social scene to which you aspire to join. They appeared to be friends with other 'relevant' individuals in your field/social scene, and a cursory perusal of their Facebook photos indicated that they have a pretty sweet life into which you fantasized you might be invited. You felt an illogical sense of flattery that this person somehow sought you out and 'friended' you, and wondered 'is this person familiar with my work/identity, do they want to offer me a job/sweet party invite'.
The person has never contacted you and has generally never actually acknowledged your existence except to send you self-promotional invites to things like their friend's gigs that cost some money to attend, their friend's gallery opening in a place too inaccessible relative to your living situation, or otherwise annoying all-caps bulletins that are not of actual interest to you. Their 'feed' is clotted with links to obvious news articles and impersonal information that appears nearly unintelligible/useless. You become aware the person has over 1000 Facebook 'friends' and does not use the social network to be social or to network. You should delete this person from your friends list.
The Attractive Person You Do Not Actually Know
You received a friend request from someone you felt you did not know, and clicking on their profile to examine everything further revealed that all of the data was set to private except for the profile photo, which was noticeably attractive to you in a fashion that made you fantasize about meeting/dating/sleeping with this person, so you overcame a vague wariness of strangers to see what this good-looking individual might possibly want with you and accepted the friend request.
You might have even one night decided to overcome the awkwardness of actual non-acquaintance to Facebook-chat the attractive stranger on Facebook, but in most cases the unsettling gap between 'Facebook friend' and 'real friend' has ultimately formed an insurmountable wall to you actually meeting this person, despite the occasional message from one or the other of you listlessly suggesting you should hang out or apologizing for going months without answering a message suggesting you should hang out or proposing plans that never materialize. This person never lists their 'relationship status'.
Instead of periodically browsing this person's photos, scrutinizing pictures of them with friends to try to discern whether they are actually/were ever single/are still available, or just generally gazing creepily at this person, you don't actually know and probably will never, you should delete them from your Facebook friends list.
The 'Ever-Present Near-Stranger'
This is an individual whereby you 'kind of know who they are' via having met them at a few parties or having worked with the company or individual for whom they work or having 'seen them around' on several occasions. This person seemed faultlessly nice if not especially unusual or piquant, so when they sent you a friend request you accepted it without much further consideration, i.e. 'I know him/her, he/she seems nice.'
Since the time you accepted that friend request, the individual comments on and/or likes nearly every 'status update' or photo you post. They feel the need to 'weigh in' on discussion threads among you and people they don't know, they post '???' when your friend leaves an inside joke on your 'wall', and every time you change your profile photo they write 'Great photo!' They employ a lot of exclamation points and generally use 'emoticons' liberally.
You examine your Facebook page and notice that should anyone examine your Facebook page in an attempt to assess you or your life, one would assume that this individual is in fact a very close friend of yours and not someone you hardly know who seems to be very involved in your Facebook page for no apparent reason and in a fashion you do not reciprocate. You feel vaguely guilty about detaching yourself from someone just because they seem to like you/your life too much, and you occasionally halfheartedly 'like' some things on their Facebook page out of a sense of obligation.
You are also aware that should you 'unfriend' this person he/she is liable to immediately notice, given how attentive he/she seems to be to your page. They will live. You should delete them from your friends list.