How To NOT Remain Friends

Don't worry, I am not about to break up with my man and tell you I don't even want to remain friends with him. I love him and even though we seem to fight considerably more these days, I couldn't live without him. 
No, this is about the difficulty to dissolve friendships or other relations and the lack of guidance there is around for that. 
There are hundreds and hundreds of advice websites, books, blogs, etc, etc which tell you how to break up with your boyfriend and try to remain friends (or not), but no guides on how to ditch a friend. 
At the moment I am reading the stories of the ingenious Marian Keyes (God, I love her) and she pondered in a short (and very funny, it's Marian Keyes, after all) sentence that you never learn how to break up with friends and it made me think about it. 
I have a very bad relation to friendships - all people in my family have. We are five people, my mum, dad and my two sisters and I, and ever since I was born it was the five of us against the world. Our mother protected us from everyone, with good intentions, but my sisters and I all have problems finding suitable friends. The issue with that is that my mother - bless her - made the big mistake to raise us to have expectations of our friends. Baaaaaad mistake. It led to me being permanently let down. 
When I was at Montessori school, I had three close friends, one of which was a bit of an independent know-it-all and when she VOLUNTARILY left school and therefore her friends, I was so sorely disappointed in her that we weren't friends anymore (I'm not saying this problem solely relies on other people, in case you were wondering). 
When I entered high school, I met a girl called Nina who became my best friend. I even chose her, but I always choose the outsiders - probably because I am one myself. 
Anyway, we remained friends all through the four years of school but then she decided her boyfriend was more important to her and I decided I don't need friends who don't give a shit about me, so I dumped her. 
A couple of years ago, I had a big meltdown (I was seventeen, you have to start early if you want to do it successfully) and ended the friendship with a childhood friend because I simply couldn't deal with her anymore at that time. This is particularly horrible, it was not about not wanting or having lost interest, but genuinely not being able to keep up a relation with a person which, at that point, was costing too much of my energy. I was devastated. We had a big fight - understandably, as there are no guides how to gently let down a friend - and didn't see each other for some time and whenever I knew she was in town, I was slightly anxious and prayed we wouldn't run into each other because I felt so crap about the situation. 
Also with Nina the high school friend. We didn't have a fight. At some point, I simply stopped talking to her, but for a long while I dreaded seeing her and whoever has been to Innsbruck knows that there is a GOOD FUCKING CHANCE you will, as it is quite a small city. 
The best way probably, but for it to work both parties have to have lost interest, is the slowly-growing-apart-and-then-realising-you-have-nothing-in-common-with-this-person-anymore method, like it happened with me and some childhood friends. You will still be kind when you meet and probably even say "we really should meet up and chat", but both parties know it will never ever happen. 
So why is there no such thing as a guide to breaking up with your friend? Possibly, because it is required of you to stay with the people you choose (scary thought, I will never choose another friend anymore) or because it is different to say things like "you are weird and most things you do are boring and I don't want to hear anything about it anymore, please leave me in peace" in a non-offensive manner.
This actually brings me to another subject I wanted to talk about and I apologise for my flimsy mind, but it will be a short digression. I think it is very interesting that the better you know (and like) a person, the ruder you get. Shouldn't it be vice versa? Probably not, as you can only be completely yourself with people you can trust won't leave you immediately for naughty behaviour. For instance, one of my dear friends is a gamer and she talks about computer games a lot and people who know me know that I HATE computer games and think they're the worst waste of time. However, instead of saying I am not interested, I keep smiling and nodding and then slowly start to tick off the list for the week in my head while she continues to talk about games (always asking "do you know that..." and I am like "no, stop asking me, when it comes to games, I don't not ANYTHING and it makes me feel stupid and old if you permanently talk about things I don't know" - of course, I only say these things in my head, to her I say "I think I have heard of it.")
The reason why I listen to her is, of course, because I have no courage...no, kidding, because I care about her and also because I guess she has to listen to a lot of my shit she isn't particularly interested in. However, when my man starts explaining about games (he is a gamer too, what kind of vibes do I send out?), I say "my darling love, I love you, but please  shut up." Why wouldn't I listen to him out of politeness? Well, I guess it is as I always say (and with always I mean it just popped into my head) "if you have good friends, you listen. If you have even better friends, you don't." My man is the only person in the world with whom I am exactly like with my family. I don't listen to him and admit it if he asks; I insult him if necessary; we tease each other constantly; criticise our clothing style, etc, etc...still, we love each other to bits. 
Probably we should use the same, lame tricks when it comes to breaking up with a friend. "It's not your fault that I perceive you as so boring", "I will always remember our time with a smile in my mind (and now especially as I don't have to see you anymore)" or "I feel like I have outgrown this relationship, I am a much better person now." 
Alright, slightly exaggerated now and then, but you get the point, right? Well, at the moment I have no friends to ditch and am quite happy with the people around me, but whenever I should come into the situation where I want a friend to get lost, I might write a friend breaking up guidance book and people all over the world will read it and call their friends, saying "Look, I've recently read this book and I think we need to talk" and the friend will answer "Funny story, I was just about to say the same" and I will make a shitload of money for breaking people up, but, hey, they will do it in a manner where they might even remain friends thereafter... 
​