If you think you can't live without any of those then you're in an excellent position to reap the benefits of doing without them. If you could easily live without them then the gain will likely be small.
In the most literal sense you're absolutely right of course. You can live without them. However, the real world isn't doesn't work on such absolutes.
Social isolation and loneliness are dibilitating conditions that can lead to serious mental illness (depression, anxiety, etc), so if you're not in a position to socialise without at least Facebook or a smartphone you should think twice before cancelling them. Many, many people would find themselves left out of group events if they cancelled their social media accounts. It's the de facto way of organising things these days. That is something that's well worth thinking about before making the leap.
I've spent long periods of my life working from remote locations, and without an internet connection to talk to my friends it would have (figuratively) killed me.
The worst is when people post photos with their significant others. I'm single... so yeah. Right in the feeler, man.
The only reason I have my account and try to be active on it is because my parents are overseas and my mom feels really disconnected if I don't.
Friends ask each other what they are up to. Just because you're all on Facebook doesn't mean you stop talking to each other about events, etc. If you can only stay in the loop because of Facebook, that speaks more about the closeness of relationships you have with your friends.
I've had a very enjoyable social life as a mid 20s guy (who deleted Facbeook) who goes out a lot and likes to make new friends. It felt like a risky move at the time, but deleting Facebook may honestly be the best decision I've made in the last year.
Mainly, people are afraid of being judged for not having Facebook. In reality, most people don't care, and it is easy to take higher ground if someone does decide to judge you, because it is a little crazy (or arguably very crazy) to make your social life dependent on a website; tell them that if you have to.
Texting, calling, and email are the bare necessities IMO, and that does not take a smartphone either. As a side note I think extremely low investment social apps like WhatsApp or Skype are very different than Facebook and nice to use.
I am.introvert, and had no examples, my dad is a loner, and orphan to boot, I was never encouraged to go out and find friends.
The few friends I have invite me over about twice a year, and using Facebook, if I deleted my Facebook I could provably drop dead in my apartment, my family would notice in 3 days, and my friends would never go to my funeral, because they would never know, maybe wonder after five years what I am doing with my life...
It's something that's 100% in your hands right now. Go out and meet people. Get yourself on a path to being someone who is more social and outgoing. There's nothing preventing you, with time, from having more (better) friends and being just as social as others. It's very human. Starting points can be Meetup groups, hobbies, co-workers, even pickup people if you want to meet girls/guys, it doesn't really matter... just start getting yourself out there, and practice turning acquaintances into friendships.
The things that facebook (and twitter) has the market cornered on are the things that no one cares about. For example, with these sites, you can see random updates from old acquaintances that really do not impact your life. That would never have happened before social media, and personally, I did not feel that 140 character quips, infini-scrolling feeds of irrelevant info, or gossiping were benefiting my life at all, so I've been on a deactivation spree.
I get by just fine.
I watch people fiddling with their smartphones everywhere I go (my girlfriend is one them... she can't sit through dinner without texting or taking a picture of the meal and posting it somewhere...does anyone care?) and wonder what they get out it.
I love computers and technology. I love to sit and code for hours. I love reading HN and posting irrelevant comments like this one. But then I stand up and walk away and HN doesn't follow me. I might be getting old but I just don't get it. I simply couldn't handle being connected all the time.
The truth is that modern commercial media are very consciously designed to be highly addictive, including TV, Facebook, many websites, and other media.
Source: I've worked in the field for much of the past decade, and could cite media executives talking about creating addictive and compelling content, dominating "all screens" -- phone, tablet, laptop, PC, and small and large-screen TVs.
It's also very difficult to find places in public where you're not assaulted by TVs, including increasingly in bars and cafes.
The salient characteristic of peer pressure is that it's not easily ignored -- that's precisely why peer pressure and social norms are sought by marketers, propagandists, and others who seek to influence group behaviors.
See: http://www.wired.com/2014/08/i-liked-everything-i-saw-on-fac...
Or discussions I've had on "the dopamine meme", TED, and weaponized viral clickbait:
http://www.reddit.com/r/dredmorbius/comments/240xss/the_dopa...
http://gigaom.com/2012/09/02/when-did-addiction-become-a-goo...
http://www.truth-out.org/opinion/item/17021-society-of-addic...
http://www.reddit.com/r/dredmorbius/comments/1te3hz/we_need_...
http://www.reddit.com/r/dredmorbius/comments/23twec/weaponiz...
And the Medium is the Message: how incentives shape what we're offered
http://www.reddit.com/r/dredmorbius/comments/278e2o/the_medi...
I tend to avoid a great deal of the dopamine-industrial complex myself. That's part of what makes it so apparent to me. I'm also aware of how compelling certain aspects of it can be.
The fact that you think you've got a strong resistance to it (which may well not be the case -- self-assessed capabilities are notoriously unreliable, see also Dunning-Kruger effect) doesn't mean that much of the world doesn't.